diff --git a/app/dao/notifications_dao.py b/app/dao/notifications_dao.py
index 3985f3ea0..cebb1964d 100644
--- a/app/dao/notifications_dao.py
+++ b/app/dao/notifications_dao.py
@@ -1,9 +1,11 @@
 import uuid
+import pytz
 from datetime import (
     datetime,
     timedelta,
     date
 )
+from itertools import groupby
 
 from flask import current_app
 from werkzeug.datastructures import MultiDict
@@ -212,20 +214,25 @@ def get_notifications_for_job(service_id, job_id, filter_dict=None, page=1, page
 @statsd(namespace="dao")
 def get_notification_billable_unit_count_per_month(service_id, year):
     start, end = get_financial_year(year)
-    return db.session.query(
-        func.to_char(NotificationHistory.created_at, "FMMonth"),
-        func.sum(NotificationHistory.billable_units)
-    ).group_by(
-        func.to_char(NotificationHistory.created_at, "FMMonth"),
-        func.to_char(NotificationHistory.created_at, "YYYY-MM")
+
+    notifications = db.session.query(
+        NotificationHistory.created_at,
+        NotificationHistory.billable_units
     ).order_by(
-        func.to_char(NotificationHistory.created_at, "YYYY-MM")
+        NotificationHistory.created_at
     ).filter(
         NotificationHistory.service_id == service_id,
         NotificationHistory.created_at >= start,
         NotificationHistory.created_at < end
     ).all()
 
+    return [
+        (month, sum(count for _, count in row))
+        for month, row in groupby(
+            notifications, lambda row: get_bst_month(row[0])
+        )
+    ]
+
 
 @statsd(namespace="dao")
 def get_notification_with_personalisation(service_id, notification_id, key_type):
@@ -340,7 +347,17 @@ def dao_timeout_notifications(timeout_period_in_seconds):
 
 
 def get_financial_year(year):
-    return (
-        date(year, 4, 1),
-        date(year + 1, 4, 1)
-    )
+    return (get_april_fools(year), get_april_fools(year + 1))
+
+
+def get_april_fools(year):
+    return datetime(
+        year, 4, 1, 0, 0, 0, 0,
+        pytz.timezone("Europe/London")
+    ).astimezone(pytz.utc)
+
+
+def get_bst_month(datetime):
+    return pytz.utc.localize(datetime).replace(
+        tzinfo=pytz.timezone("Europe/London")
+    ).strftime('%B')
diff --git a/tests/app/dao/test_notification_dao.py b/tests/app/dao/test_notification_dao.py
index 51fa9284b..7e7ac1d18 100644
--- a/tests/app/dao/test_notification_dao.py
+++ b/tests/app/dao/test_notification_dao.py
@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta, date
+import pytz
 import uuid
 from functools import partial
 
@@ -690,18 +691,21 @@ def test_get_all_notifications_for_job_by_status(notify_db, notify_db_session, s
 def test_get_notification_billable_unit_count_per_month(notify_db, notify_db_session, sample_service):
 
     for year, month, day in (
-        (2017, 1, 1),
+        (2017, 1, 1),  # ↓ 2016 financial year
         (2016, 8, 1),
         (2016, 7, 31),
         (2016, 4, 6),
         (2016, 4, 6),
-        (2016, 4, 1),
+        (2016, 4, 1),  # ↓ 2015 financial year
         (2016, 3, 31),
         (2016, 1, 1)
     ):
         sample_notification(
             notify_db, notify_db_session, service=sample_service,
-            created_at=date(year, month, day)
+            created_at=datetime(
+                year, month, day, 0, 0, 0, 0,
+                tzinfo=pytz.utc
+            )
         )
 
     for financial_year, months in (
@@ -711,11 +715,11 @@ def test_get_notification_billable_unit_count_per_month(notify_db, notify_db_ses
         ),
         (
             2016,
-            [('April', 3), ('July', 1), ('August', 1), ('January', 1)]
+            [('April', 2), ('July', 1), ('August', 1), ('January', 1)]
         ),
         (
             2015,
-            [('January', 1), ('March', 1)]
+            [('January', 1), ('March', 1), ('April', 1)]
         ),
         (
             2014,
@@ -1204,5 +1208,7 @@ def test_should_exclude_test_key_notifications_by_default(
 
 def test_get_financial_year():
     start, end = get_financial_year(2000)
-    assert start == date(2000, 4, 1)
-    assert end == date(2001, 4, 1)
+    assert start.tzinfo == pytz.utc
+    assert start.isoformat() == '2000-04-01T00:01:00+00:00'
+    assert end.tzinfo == pytz.utc
+    assert end.isoformat() == '2001-04-01T00:01:00+00:00'