diff --git a/swmmanywhere/paper/experimenter.py b/swmmanywhere/paper/experimenter.py
index aae3e03a..55947887 100644
--- a/swmmanywhere/paper/experimenter.py
+++ b/swmmanywhere/paper/experimenter.py
@@ -118,7 +118,12 @@ def process_parameters(jobid: int,
     """Generate and run parameter samples for the sensitivity analysis.
 
     This function generates parameter samples and runs the swmmanywhere model
-    for each sample. It is designed to be run in parallel as a jobarray.
+    for each sample. It is designed to be run in parallel as a jobarray. It 
+    selects parameters values from the generated ones based on the jobid and 
+    the number of processors. It copies the config file and passes these 
+    parameters into swmmanywhere via the `parameter_overrides` property. Existing
+    overrides that are not being sampled are retained, existing overrides that 
+    are being sampled are overwritten by the sampled value.
 
     Args:
         jobid (int): The job id.
@@ -160,11 +165,16 @@ def process_parameters(jobid: int,
                                         "param", 
                                         "value"]].itertuples(index=False, 
                                                              name=None):
-            if grp not in overrides:
+            
+            # Experimenter overrides take precedence over the config file
+            if grp in config.get('parameter_overrides',{}):
+                overrides[grp] = config['parameter_overrides'][grp]
+            elif grp not in overrides:
                 overrides[grp] = {}
-            overrides[grp][param] = val
-        config['parameter_overrides'].update(overrides)
 
+            overrides[grp][param] = val       
+        config['parameter_overrides'] = overrides
+        
         # Run the model
         config['model_number'] = ix
         logger.info(f"Running swmmanywhere for model {ix}")
diff --git a/tests/test_experimenter.py b/tests/test_experimenter.py
index 37c40bc6..afd5cfb3 100644
--- a/tests/test_experimenter.py
+++ b/tests/test_experimenter.py
@@ -1,6 +1,8 @@
 """Tests for the main experimenter."""
 from __future__ import annotations
 
+from unittest import mock
+
 import numpy as np
 
 from swmmanywhere import parameters
@@ -41,4 +43,38 @@ def test_generate_samples():
                             seed = 1,
                             groups = True)
     assert len(samples) == 36
-    
\ No newline at end of file
+
+def test_process_parameters():
+    """Test process_parameters."""
+    config = {'parameters_to_sample' : ['min_v','max_v'],
+              'sample_magnitude' : 3,
+              }
+
+    # Test standard 
+    with mock.patch('swmmanywhere.paper.experimenter.swmmanywhere.swmmanywhere', 
+                    return_value=('fake_path',{'fake_metric' : 1})) as mock_sa:
+        result = experimenter.process_parameters(0,1,config)
+    
+    assert len(result[0]) == 48
+    assert_close(result[0][0]['min_v'], 0.310930)
+
+    # Test experimenter takes precedence over overrides 
+    config['parameter_overrides'] = {'hydraulic_design': {'min_v': 1.0}}
+    with mock.patch('swmmanywhere.paper.experimenter.swmmanywhere.swmmanywhere', 
+                    return_value=('fake_path',{'fake_metric' : 1})) as mock_sa:
+        result = experimenter.process_parameters(0,1,config)
+    
+    assert len(result[0]) == 48
+    assert_close(result[0][0]['min_v'], 0.310930)
+
+    # Test non experimenter overrides still work 
+    config['parameter_overrides'] = {'hydraulic_design': {'max_fr': 0.5}}
+    with mock.patch('swmmanywhere.paper.experimenter.swmmanywhere.swmmanywhere', 
+                    return_value=('fake_path',{'fake_metric' : 1})) as mock_sa:
+        result = experimenter.process_parameters(0,1,config)
+
+    for call in mock_sa.mock_calls:
+        assert call.args[0]['parameter_overrides']['hydraulic_design']['max_fr'] == 0.5
+
+    assert len(result[0]) == 48
+    assert_close(result[0][0]['min_v'], 0.310930)
\ No newline at end of file