diff --git a/core/migrations/0018_alter_attrition_cost_centre_and_more.py b/core/migrations/0018_alter_attrition_cost_centre_and_more.py
new file mode 100644
index 00000000..59266439
--- /dev/null
+++ b/core/migrations/0018_alter_attrition_cost_centre_and_more.py
@@ -0,0 +1,51 @@
+# Generated by Django 5.1.3 on 2024-12-10 13:53
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("core", "0017_alter_attrition_cost_centre_and_more"),
+        ("costcentre", "0008_alter_simplehistoryarchivedcostcentre_options_and_more"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="attrition",
+            name="cost_centre",
+            field=models.ForeignKey(
+                blank=True,
+                null=True,
+                on_delete=django.db.models.deletion.PROTECT,
+                to="costcentre.costcentre",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="attrition",
+            name="financial_year",
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.PROTECT, to="core.financialyear"
+            ),
+        ),
+        migrations.AlterField(
+            model_name="payuplift",
+            name="financial_year",
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.PROTECT, to="core.financialyear"
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name="attrition",
+            constraint=models.UniqueConstraint(
+                fields=("financial_year", "cost_centre"), name="unique_attrition"
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name="payuplift",
+            constraint=models.UniqueConstraint(
+                fields=("financial_year",), name="unique_pay_uplift"
+            ),
+        ),
+    ]
diff --git a/core/models.py b/core/models.py
index ddb438a9..7b43fdbf 100644
--- a/core/models.py
+++ b/core/models.py
@@ -97,9 +97,7 @@ class Meta:
     def periods(self) -> list[float]:
         return [getattr(self, month) for month in MONTHS]
 
-    financial_year = models.ForeignKey(
-        FinancialYear, on_delete=models.PROTECT, unique=True
-    )
+    financial_year = models.ForeignKey(FinancialYear, on_delete=models.PROTECT)
     apr = models.FloatField(default=1.0)
     may = models.FloatField(default=1.0)
     jun = models.FloatField(default=1.0)
@@ -115,19 +113,36 @@ def periods(self) -> list[float]:
 
 
 class PayUplift(PayModifiers):
-    pass
+    class Meta:
+        constraints = (
+            models.UniqueConstraint(
+                fields=[
+                    "financial_year",
+                ],
+                name="unique_pay_uplift",
+            ),
+        )
 
 
 class Attrition(PayModifiers):
     class Meta:
         verbose_name_plural = "attrition"
 
+        constraints = (
+            models.UniqueConstraint(
+                fields=[
+                    "financial_year",
+                    "cost_centre",
+                ],
+                name="unique_attrition",
+            ),
+        )
+
     cost_centre = models.ForeignKey(
         "costcentre.CostCentre",
         on_delete=models.PROTECT,
         null=True,
         blank=True,
-        unique=True,
     )