diff --git a/lib/assets/stylesheets/_govuk_tech_docs.scss b/lib/assets/stylesheets/_govuk_tech_docs.scss
index 61b76a3a..3080ec35 100644
--- a/lib/assets/stylesheets/_govuk_tech_docs.scss
+++ b/lib/assets/stylesheets/_govuk_tech_docs.scss
@@ -1,4 +1,4 @@
-$govuk-assets-path: "/assets/govuk/assets/";
+$govuk-assets-path: "/assets/govuk/assets/" !default;
 
 // Include only the bits of GOV.UK Frontend we need
 $govuk-new-link-styles: true;
diff --git a/lib/assets/stylesheets/modules/_anchored-heading.scss b/lib/assets/stylesheets/modules/_anchored-heading.scss
index eda7834c..962cb395 100644
--- a/lib/assets/stylesheets/modules/_anchored-heading.scss
+++ b/lib/assets/stylesheets/modules/_anchored-heading.scss
@@ -18,12 +18,12 @@
     text-decoration: none;
     text-indent: -9999em;
 
-    background-image: url('/images/anchored-heading-icon.png');
+    background-image: image-url('/images/anchored-heading-icon.png');
     background-repeat: no-repeat;
     background-position: center center;
 
     @include govuk-device-pixel-ratio {
-      background-image: url('/images/anchored-heading-icon-2x.png');
+      background-image: image-url('/images/anchored-heading-icon-2x.png');
       background-size: $icon-width $icon-height;
     }
 
diff --git a/lib/assets/stylesheets/modules/_search.scss b/lib/assets/stylesheets/modules/_search.scss
index e13bda18..9bde54cd 100644
--- a/lib/assets/stylesheets/modules/_search.scss
+++ b/lib/assets/stylesheets/modules/_search.scss
@@ -36,7 +36,7 @@ $input-size: 40px;
   padding: 0;
   width: $input-size;
   height: 100%;
-  background-image: url('/images/search-button.png');
+  background-image: image-url('/images/search-button.png');
   background-repeat: no-repeat;
   background-position: 2px 50%;
   text-indent: -5000px;
@@ -104,7 +104,7 @@ $input-size: 40px;
       left: -9px;
       width: 10px;
       height: 20px;
-      background: no-repeat url('/images/search-result-caret.svg') center right;
+      background: no-repeat image-url('/images/search-result-caret.svg') center right;
       background-size: contain;
     }
   }
diff --git a/lib/assets/stylesheets/modules/_toc.scss b/lib/assets/stylesheets/modules/_toc.scss
index ff2e7085..921c5abf 100644
--- a/lib/assets/stylesheets/modules/_toc.scss
+++ b/lib/assets/stylesheets/modules/_toc.scss
@@ -152,12 +152,12 @@
           height: 20px;
           float: right;
 
-          background-image: url('/images/govuk-icn-numbered-list.png');
+          background-image: image-url('/images/govuk-icn-numbered-list.png');
           background-repeat: no-repeat;
           background-position: left center;
 
           @include govuk-device-pixel-ratio {
-            background-image: url('/images/govuk-icn-numbered-list@2x.png');
+            background-image: image-url('/images/govuk-icn-numbered-list@2x.png');
             background-size: 20px 20px;
           }
         }
@@ -178,12 +178,12 @@
         height: 20px;
         cursor: pointer;
 
-        background-image: url('/images/govuk-icn-close.png');
+        background-image: image-url('/images/govuk-icn-close.png');
         background-repeat: no-repeat;
         background-position: left center;
 
         @include govuk-device-pixel-ratio {
-          background-image: url('/images/govuk-icn-close@2x.png');
+          background-image: image-url('/images/govuk-icn-close@2x.png');
           background-size: 20px 20px;
         }