diff --git a/model_data/recommendations/WallRecommendations.py b/model_data/recommendations/WallRecommendations.py
index 47dc99d6..b4fc703e 100644
--- a/model_data/recommendations/WallRecommendations.py
+++ b/model_data/recommendations/WallRecommendations.py
@@ -191,10 +191,19 @@ class WallRecommendations(BaseUtility):
     # more popular choice
     YEARS_CAVITY_WALLS_BEGAN = 1930
     U_VALUE_UNIT = 'w/m-¦k'
-    # TODO: REVIEW THESE FIGURES: RETROFIT ACADEMY COUSE INDICATED THAT IT SHOULD BE 0.3
-    BUILDING_REGULATIONS_PART_L_MAX_U_VALUE = 0.18
-    # Often cited minimum practical u-value
-    DIMINISHING_RETURNS_U_VALUE = 0.15
+
+    # part L building regulations indicate that any rennovations on an existing property's walls should
+    # achieve a U-value of no higher than 0.3
+    BUILDING_REGULATIONS_PART_L_MAX_U_VALUE = 0.3
+    # We don't recommend measures that are too low because it becomes expensive, therefore we aim to avoid
+    # diminishing returns. This value should be verified with Osmosis (TODO)
+    DIMINISHING_RETURNS_U_VALUE = 0.25
+
+    # Part L regulations indicate that any new build should have walls that achieve a u-value of no higher
+    # than 0.18.
+    BUILDING_REGULATIONS_PART_L_NEW_BUILD_MAX_U_VALUE = 0.18
+    # 0.15 is an often cited diminishing returns value for new builds
+    NEW_BUILD_DIMINISHING_RETURNS_U_VALUE = 0.15
 
     # Add some error so that if, for example, a new part we recommend provides a u-value of 0.19,
     # we still consider it as an option
@@ -263,11 +272,25 @@ class WallRecommendations(BaseUtility):
             #       they're likely to be of a certain standard. E.g. properties built within a certain time
             #       period are likely to have cavity walls
 
+            # We can't detect it's a cavity wall, but it was built after 1990 so likely built with insulation already
+            # + it already has a U-value WORSE than the building regulations, so we recommend either internal or
+            # external wall insulation
             if (not is_cavity_wall) and (self.year_built >= self.YEAR_WALLS_BUILT_WITH_INSULATION) and (
                 u_value >= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE
             ):
                 # Recommend insulation
                 self.find_insulation(u_value)
+                return
+
+            # We can't detect it's a cavity wall, but it was built after 1990 so likely built with insulation already
+            # + it already has a U-value better than the building regulations, so we don't need to recommend anything
+            if (not is_cavity_wall) and (self.year_built >= self.YEAR_WALLS_BUILT_WITH_INSULATION) and (
+                u_value <= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE
+            ):
+                # Recommend nothing
+                return
+
+            raise NotImplementedError("Not implemented yet")
 
         if is_solid_brick:
 
@@ -279,6 +302,7 @@ class WallRecommendations(BaseUtility):
 
             if u_value >= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE:
                 self.find_insulation(u_value)
+                return
 
         raise NotImplementedError("Not implemented yet")
 
@@ -303,9 +327,9 @@ class WallRecommendations(BaseUtility):
 
                 _, new_u_value = self.calculate_u_value_uplift(u_value, part_u_value)
                 new_u_value = round(new_u_value, 2)
-
-                if new_u_value < self.DIMINISHING_RETURNS_U_VALUE:
-                    # We don't recommend an overkill solution
+                if new_u_value < self.DIMINISHING_RETURNS_U_VALUE and self.recommendations:
+                    # If we already have a solution that is suitable and does not cross the diminishing returns
+                    # threshold, but meets the part L requirements, we don't need to recommend anything
                     continue
 
                 # We allow a small tolerance for error so we don't discount the recommendation entirely
diff --git a/model_data/tests/test_data/uvalue_estimates_walls.pkl b/model_data/tests/test_data/uvalue_estimates_walls.pkl
new file mode 100644
index 00000000..2db094e6
Binary files /dev/null and b/model_data/tests/test_data/uvalue_estimates_walls.pkl differ
diff --git a/model_data/tests/test_wall_recommendations.py b/model_data/tests/test_wall_recommendations.py
index ab98e5ba..106e30ec 100644
--- a/model_data/tests/test_wall_recommendations.py
+++ b/model_data/tests/test_wall_recommendations.py
@@ -20,6 +20,59 @@ class TestWallRecommendations:
         ) as f:
             return pickle.load(f)
 
+    def test_init(self, input_properties, uvalue_estimates):
+        obj = WallRecommendations(property_instance=input_properties[0], uvalue_estimates=uvalue_estimates)
+        assert obj
+        assert obj.property
+        assert obj.uvalue_estimates
+
+        assert obj.year_built == 2014
+
+    def test_uvalue_0_16(self, input_properties, uvalue_estimates):
+        """
+        This tests the wall description Average thermal transmittance 0.16 W/m-¦K
+        The important data for this recommendation is:
+        - u value of 0.16
+        - property built in 2014
+        Since properties built after 1990 are typically built with insulation and this property
+        already has really good insulation, we do NOT recommend any measures for this property
+        """
+        recommender = WallRecommendations(property_instance=input_properties[0], uvalue_estimates=uvalue_estimates)
+        assert recommender.property.walls["original_description"] == "Average thermal transmittance 0.16 W/m-¦K"
+        assert recommender.year_built == 2014
+        recommender.recommend()
+        # This should be empty
+        assert recommender.recommendations == []
+
+    def test_solid_brick_no_insulation(self, input_properties, uvalue_estimates):
+        """
+        This tests a property with a wall description of Solid brick, as built, no insulation (assumed)
+        The property was built in 1930, right on the threshold for when cavity walls were introduced
+        However, we're told this property is solid brik so we assume no cavity.
+        We're also told that it has no insulation, so we will recommend internal/external wall insulation
+
+        This property is not in a conservation area, however it's a flat so we don't recommend external wall insulation
+        """
+        recommender = WallRecommendations(property_instance=input_properties[1], uvalue_estimates=uvalue_estimates)
+        assert recommender.property.walls["original_description"] == "Solid brick, as built, no insulation (assumed)"
+        assert recommender.year_built == 1930
+        assert not recommender.ewi_valid
+        assert recommender.property.in_conservation_area == "not_in_conservation_area"
+        assert recommender.property.data["property-type"] == "Flat"
+
+        recommender.recommend()
+        # This should result in some recommendations, all of which should be insulation
+        assert recommender.recommendations
+
+        rec_types = {rec["type"] for rec in recommender.recommendations}
+        assert rec_types == {"internal_wall_insulation"}
+
+        # Check the recommendations provide a u value below the minimum
+        assert all(
+            rec["new_u_value"] < WallRecommendations.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE for rec in
+            recommender.recommendations
+        )
+
     def test_nothing(self, input_properties, uvalue_estimates):
         assert input_properties
         assert uvalue_estimates