diff --git a/src/ORM/Validation/RelationValidationService.php b/src/Dev/Validation/RelationValidationService.php
similarity index 99%
rename from src/ORM/Validation/RelationValidationService.php
rename to src/Dev/Validation/RelationValidationService.php
index 485809161d4..7531f741441 100644
--- a/src/ORM/Validation/RelationValidationService.php
+++ b/src/Dev/Validation/RelationValidationService.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace SilverStripe\ORM\Validation;
+namespace SilverStripe\Dev\Validation;
 
 use ReflectionException;
 use SilverStripe\Core\ClassInfo;
@@ -18,8 +18,6 @@
  *
  * This tool runs automatically via dev/build and outputs notices
  * For strict validation it is recommended to hook this up to your unit test suite
- *
- * @package SilverStripe\ORM\Validation
  */
 class RelationValidationService implements Resettable
 {
diff --git a/src/ORM/DataObject.php b/src/ORM/DataObject.php
index 0d0910aeb05..3052e390c53 100644
--- a/src/ORM/DataObject.php
+++ b/src/ORM/DataObject.php
@@ -12,6 +12,7 @@
 use SilverStripe\Core\Resettable;
 use SilverStripe\Dev\Debug;
 use SilverStripe\Dev\Deprecation;
+use SilverStripe\Dev\Validation\RelationValidationService;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\FormField;
 use SilverStripe\Forms\FormScaffolder;
@@ -3650,7 +3651,12 @@ public function requireDefaultRecords()
             }
         }
 
-        // Let any extentions make their own database default data
+        // Validate relations (this needs to be triggered only once)
+        if (static::class === \Page::class) {
+            RelationValidationService::singleton()->devBuildCheck();
+        }
+
+        // Let any extensions make their own database default data
         $this->extend('requireDefaultRecords', $dummy);
     }
 
diff --git a/tests/php/ORM/Validation/Freelancer.php b/tests/php/Dev/Validation/Freelancer.php
similarity index 93%
rename from tests/php/ORM/Validation/Freelancer.php
rename to tests/php/Dev/Validation/Freelancer.php
index 2028d7864a0..7a00896aecc 100644
--- a/tests/php/ORM/Validation/Freelancer.php
+++ b/tests/php/Dev/Validation/Freelancer.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace SilverStripe\ORM\Tests\Validation;
+namespace SilverStripe\Dev\Tests\Validation;
 
 use SilverStripe\Dev\TestOnly;
 use SilverStripe\ORM\DataObject;
diff --git a/tests/php/ORM/Validation/Hat.php b/tests/php/Dev/Validation/Hat.php
similarity index 94%
rename from tests/php/ORM/Validation/Hat.php
rename to tests/php/Dev/Validation/Hat.php
index a36bba6d9f3..b4cfc407d09 100644
--- a/tests/php/ORM/Validation/Hat.php
+++ b/tests/php/Dev/Validation/Hat.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace SilverStripe\ORM\Tests\Validation;
+namespace SilverStripe\Dev\Tests\Validation;
 
 use SilverStripe\Dev\TestOnly;
 use SilverStripe\ORM\DataObject;
diff --git a/tests/php/ORM/Validation/Member.php b/tests/php/Dev/Validation/Member.php
similarity index 95%
rename from tests/php/ORM/Validation/Member.php
rename to tests/php/Dev/Validation/Member.php
index 13418c1d090..1af4a81f7ce 100644
--- a/tests/php/ORM/Validation/Member.php
+++ b/tests/php/Dev/Validation/Member.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace SilverStripe\ORM\Tests\Validation;
+namespace SilverStripe\Dev\Tests\Validation;
 
 use SilverStripe\Dev\TestOnly;
 use SilverStripe\ORM\DataObject;
diff --git a/tests/php/ORM/Validation/RelationValidationTest.php b/tests/php/Dev/Validation/RelationValidationTest.php
similarity index 83%
rename from tests/php/ORM/Validation/RelationValidationTest.php
rename to tests/php/Dev/Validation/RelationValidationTest.php
index a5ed3f8e34e..b609b68f00f 100644
--- a/tests/php/ORM/Validation/RelationValidationTest.php
+++ b/tests/php/Dev/Validation/RelationValidationTest.php
@@ -1,11 +1,11 @@
 <?php
 
-namespace SilverStripe\ORM\Tests\Validation;
+namespace SilverStripe\Dev\Tests\Validation;
 
 use Page;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Dev\SapphireTest;
-use SilverStripe\ORM\Validation\RelationValidationService;
+use SilverStripe\Dev\Validation\RelationValidationService;
 
 class RelationValidationTest extends SapphireTest
 {
@@ -78,8 +78,8 @@ public function validateCasesProvider(): array
                     'Hatter' => Member::class,
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Member / Hat : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Hat / Hatter : Relation is not in the expected format (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Member / Hat : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Hat / Hatter : Relation is not in the expected format (needs class.relation format)',
                 ],
             ],
             'ambiguous has_one - incorrect relation name' => [
@@ -89,8 +89,8 @@ public function validateCasesProvider(): array
                     'Hatter' => Member::class . '.ObviouslyWrong',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Member / Hat : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Hat / Hatter : Back relation not found',
+                    'SilverStripe\Dev\Tests\Validation\Member / Hat : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Hat / Hatter : Back relation not found',
                 ],
             ],
             'ambiguous has_one - too many relations' => [
@@ -101,7 +101,7 @@ public function validateCasesProvider(): array
                     'HatterCopy' => Member::class . '.Hat',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Member / Hat : Back relation is ambiguous',
+                    'SilverStripe\Dev\Tests\Validation\Member / Hat : Back relation is ambiguous',
                 ],
             ],
             'invalid has one' => [
@@ -112,7 +112,7 @@ public function validateCasesProvider(): array
                     'Hat' => Hat::class,
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Member / HomeTeam : Relation SilverStripe\ORM\Tests\Validation\Team.UnnecessaryRelation is not in the expected format (needs class only format).'
+                    'SilverStripe\Dev\Tests\Validation\Member / HomeTeam : Relation SilverStripe\Dev\Tests\Validation\Team.UnnecessaryRelation is not in the expected format (needs class only format).'
                 ],
             ],
             'ambiguous has_many - no relation name' => [
@@ -123,8 +123,8 @@ public function validateCasesProvider(): array
                     'FreelancerMembers' => Freelancer::class . '.TemporaryTeam',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / Members : Relation is not in the expected format (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Member / HomeTeam : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Team / Members : Relation is not in the expected format (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Member / HomeTeam : Back relation not found or ambiguous (needs class.relation format)',
                 ],
             ],
             'ambiguous has_many - incorrect relation name' => [
@@ -135,8 +135,8 @@ public function validateCasesProvider(): array
                     'FreelancerMembers' => Freelancer::class . '.TemporaryTeam',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / Members : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Member / HomeTeam : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Team / Members : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Member / HomeTeam : Back relation not found or ambiguous (needs class.relation format)',
                 ],
             ],
             'ambiguous has_many - too many relations' => [
@@ -148,7 +148,7 @@ public function validateCasesProvider(): array
                     'FreelancerMembers' => Freelancer::class . '.TemporaryTeam',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Member / HomeTeam : Back relation is ambiguous',
+                    'SilverStripe\Dev\Tests\Validation\Member / HomeTeam : Back relation is ambiguous',
                 ],
             ],
             'ambiguous many_many - no relation name' => [
@@ -158,8 +158,8 @@ public function validateCasesProvider(): array
                     'TeamHats' => Team::class,
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / ReserveHats : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Hat / TeamHats : Relation is not in the expected format (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Team / ReserveHats : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Hat / TeamHats : Relation is not in the expected format (needs class.relation format)',
                 ],
             ],
             'ambiguous many_many - incorrect relation name' => [
@@ -169,8 +169,8 @@ public function validateCasesProvider(): array
                     'TeamHats' => Team::class . '.ObviouslyWrong',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / ReserveHats : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Hat / TeamHats : Back relation not found',
+                    'SilverStripe\Dev\Tests\Validation\Team / ReserveHats : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Hat / TeamHats : Back relation not found',
                 ],
             ],
             'ambiguous many_many - too many relations' => [
@@ -181,7 +181,7 @@ public function validateCasesProvider(): array
                     'TeamHatsCopy' => Team::class . '.ReserveHats',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / ReserveHats : Back relation is ambiguous',
+                    'SilverStripe\Dev\Tests\Validation\Team / ReserveHats : Back relation is ambiguous',
                 ],
             ],
             'ambiguous many_many through - no relation name' => [
@@ -191,8 +191,8 @@ public function validateCasesProvider(): array
                     'FreelancerTeams' => Team::class,
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / Freelancers : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Member / FreelancerTeams : Relation is not in the expected format (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Team / Freelancers : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Member / FreelancerTeams : Relation is not in the expected format (needs class.relation format)',
                 ],
             ],
             'ambiguous many_many through - incorrect relation name' => [
@@ -202,8 +202,8 @@ public function validateCasesProvider(): array
                     'FreelancerTeams' => Team::class . '.ObviouslyWrong',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / Freelancers : Back relation not found or ambiguous (needs class.relation format)',
-                    'SilverStripe\ORM\Tests\Validation\Member / FreelancerTeams : Back relation not found',
+                    'SilverStripe\Dev\Tests\Validation\Team / Freelancers : Back relation not found or ambiguous (needs class.relation format)',
+                    'SilverStripe\Dev\Tests\Validation\Member / FreelancerTeams : Back relation not found',
                 ],
             ],
             'ambiguous many_many through - too many relations' => [
@@ -214,7 +214,7 @@ public function validateCasesProvider(): array
                     'FreelancerTeamsCopy' => Team::class . '.Freelancers',
                 ],
                 [
-                    'SilverStripe\ORM\Tests\Validation\Team / Freelancers : Back relation is ambiguous',
+                    'SilverStripe\Dev\Tests\Validation\Team / Freelancers : Back relation is ambiguous',
                 ],
             ],
         ];
@@ -245,7 +245,7 @@ public function ignoredClassesProvider(): array
                 Team::class,
                 'Members',
                 [
-                    'allow_rules' => ['app' => 'SilverStripe\ORM\Tests\Validation'],
+                    'allow_rules' => ['app' => 'SilverStripe\Dev\Tests\Validation'],
                 ],
                 false,
             ],
@@ -253,7 +253,7 @@ public function ignoredClassesProvider(): array
                 Team::class,
                 null,
                 [
-                    'allow_rules' => ['app' => 'SilverStripe\ORM\Tests\Validation'],
+                    'allow_rules' => ['app' => 'SilverStripe\Dev\Tests\Validation'],
                     'deny_rules' => [Team::class],
                 ],
                 true,
@@ -262,7 +262,7 @@ public function ignoredClassesProvider(): array
                 Team::class,
                 'Members',
                 [
-                    'allow_rules' => ['app' => 'SilverStripe\ORM\Tests\Validation'],
+                    'allow_rules' => ['app' => 'SilverStripe\Dev\Tests\Validation'],
                     'deny_rules' => [Team::class],
                 ],
                 true,
@@ -271,7 +271,7 @@ public function ignoredClassesProvider(): array
                 Team::class,
                 'Members',
                 [
-                    'allow_rules' => ['app' => 'SilverStripe\ORM\Tests\Validation'],
+                    'allow_rules' => ['app' => 'SilverStripe\Dev\Tests\Validation'],
                     'deny_relations' => [Team::class . '.Members'],
                 ],
                 true,
@@ -280,7 +280,7 @@ public function ignoredClassesProvider(): array
                 Member::class,
                 'HomeTeam',
                 [
-                    'allow_rules' => ['app' => 'SilverStripe\ORM\Tests\Validation'],
+                    'allow_rules' => ['app' => 'SilverStripe\Dev\Tests\Validation'],
                     'deny_rules' => [Team::class],
                     'deny_relations' => [Team::class . '.Members'],
                 ],
diff --git a/tests/php/ORM/Validation/Team.php b/tests/php/Dev/Validation/Team.php
similarity index 96%
rename from tests/php/ORM/Validation/Team.php
rename to tests/php/Dev/Validation/Team.php
index 095da1b08dd..701423380ab 100644
--- a/tests/php/ORM/Validation/Team.php
+++ b/tests/php/Dev/Validation/Team.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace SilverStripe\ORM\Tests\Validation;
+namespace SilverStripe\Dev\Tests\Validation;
 
 use SilverStripe\Dev\TestOnly;
 use SilverStripe\ORM\DataObject;