diff --git a/db/migrations/legacy/20221108007028_water-licence-version-purpose-condition-types.js b/db/migrations/legacy/20221108007028_water-licence-version-purpose-condition-types.js
index b7b5cd3f70..6297da9d4b 100644
--- a/db/migrations/legacy/20221108007028_water-licence-version-purpose-condition-types.js
+++ b/db/migrations/legacy/20221108007028_water-licence-version-purpose-condition-types.js
@@ -20,6 +20,8 @@ exports.up = function (knex) {
       // Legacy timestamps
       table.timestamp('date_created', { useTz: false }).notNullable().defaultTo(knex.fn.now())
       table.timestamp('date_updated', { useTz: false }).notNullable().defaultTo(knex.fn.now())
+
+      table.unique(['code', 'subcode'], 'uidx_code_subcode')
     })
 }
 
diff --git a/test/support/seeders/licence-version-purpose-condition-types.seeder.js b/test/support/seeders/licence-version-purpose-condition-types.seeder.js
index 7244f71f87..eaee052341 100644
--- a/test/support/seeders/licence-version-purpose-condition-types.seeder.js
+++ b/test/support/seeders/licence-version-purpose-condition-types.seeder.js
@@ -17,7 +17,13 @@ const keys = ['id', 'code', 'subcode', 'description', 'subcodeDescription', 'dis
 async function seed () {
   await db.raw(`
     INSERT INTO  public.licence_version_purpose_condition_types (id, code, subcode, description, subcode_description, display_title, created_at, updated_at)
-      VALUES ${buildSeedValueString(keys, data)};
+      VALUES ${buildSeedValueString(keys, data)}
+    ON CONFLICT (code, subcode)
+    DO UPDATE SET
+    description = excluded.description,
+    subcode_description = excluded.subcode_description,
+    display_title = excluded.display_title,
+    updated_at = now()
   `
   )
 }
diff --git a/test/support/seeders/primary-purpose.seeder.js b/test/support/seeders/primary-purpose.seeder.js
index bb0456b23b..24dfd0ffce 100644
--- a/test/support/seeders/primary-purpose.seeder.js
+++ b/test/support/seeders/primary-purpose.seeder.js
@@ -17,7 +17,11 @@ const keys = ['id', 'legacyId', 'description', 'createdAt', 'updatedAt']
 async function seed () {
   await db.raw(`
     INSERT INTO  public.primary_purposes (id, legacy_id, description, created_at, updated_at)
-      VALUES ${buildSeedValueString(keys, data)};
+      VALUES ${buildSeedValueString(keys, data)}
+    ON CONFLICT (legacy_id)
+    DO UPDATE SET
+    description = excluded.description,
+    updated_at = now()
   `
   )
 }
diff --git a/test/support/seeders/purposes.seeder.js b/test/support/seeders/purposes.seeder.js
index 50eb3e006b..756d1b874a 100644
--- a/test/support/seeders/purposes.seeder.js
+++ b/test/support/seeders/purposes.seeder.js
@@ -17,7 +17,13 @@ const keys = ['id', 'legacyId', 'description', 'lossFactor', 'twoPartTariff', 'c
 async function seed () {
   await db.raw(`
     INSERT INTO  public.purposes (id, legacy_id, description, loss_factor, two_part_tariff, created_at, updated_at)
-      VALUES ${buildSeedValueString(keys, data)};
+      VALUES ${buildSeedValueString(keys, data)}
+    ON CONFLICT (legacy_id)
+    DO UPDATE SET
+    description = excluded.description,
+    loss_factor = excluded.loss_factor,
+    two_part_tariff = excluded.two_part_tariff,
+    updated_at = now()
   `
   )
 }
diff --git a/test/support/seeders/secondary-purpose.seeder.js b/test/support/seeders/secondary-purpose.seeder.js
index e271cc1342..c96a959823 100644
--- a/test/support/seeders/secondary-purpose.seeder.js
+++ b/test/support/seeders/secondary-purpose.seeder.js
@@ -17,7 +17,11 @@ const keys = ['id', 'legacyId', 'description', 'createdAt', 'updatedAt']
 async function seed () {
   await db.raw(`
     INSERT INTO  public.secondary_purposes (id, legacy_id, description, created_at, updated_at)
-      VALUES ${buildSeedValueString(keys, data)};
+      VALUES ${buildSeedValueString(keys, data)}
+    ON CONFLICT (legacy_id)
+    DO UPDATE SET
+    description = excluded.description,
+    updated_at = now()
   `
   )
 }