attempt to pull logos from the admin app's static images directory

(this is configured by a config value)

app/celery/provider_tasks.py

@@ -1,27 +1,27 @@
 from datetime import datetime
 from monotonic import monotonic
+from urllib.parse import urljoin
+
 from flask import current_app
+from notifications_utils.recipients import (
+    validate_and_format_phone_number
+)
+from notifications_utils.template import Template, get_sms_fragment_count
+from notifications_utils.renderers import HTMLEmail, PlainTextEmail, SMSMessage
+
 from app import notify_celery, statsd_client, clients, create_uuid
 from app.clients.email import EmailClientException
 from app.clients.sms import SmsClientException
-
 from app.dao.notifications_dao import (
     update_provider_stats,
     get_notification_by_id,
     dao_update_notification,
     update_notification_status_by_id
 )
-
 from app.dao.provider_details_dao import get_provider_details_by_notification_type
 from app.dao.services_dao import dao_fetch_service_by_id
 from app.celery.research_mode_tasks import send_sms_response, send_email_response
-from notifications_utils.recipients import (
-    validate_and_format_phone_number
-)
-
 from app.dao.templates_dao import dao_get_template_by_id
-from notifications_utils.template import Template, get_sms_fragment_count
-from notifications_utils.renderers import HTMLEmail, PlainTextEmail, SMSMessage
 
 from app.models import SMS_TYPE, EMAIL_TYPE, KEY_TYPE_TEST, BRANDING_ORG
 from app.statsd_decorators import statsd
@@ -190,9 +190,14 @@ def send_email_to_provider(self, service_id, notification_id):
 def get_html_email_renderer(service):
     govuk_banner = service.branding != BRANDING_ORG
     if service.organisation:
+        logo = '{}{}{}'.format(
+            current_app.config['ADMIN_BASE_URL'],
+            current_app.config['BRANDING_PATH'],
+            service.organisation.logo
+        )
         branding = {
             'brand_colour': service.organisation.colour,
-            'brand_logo': service.organisation.logo,
+            'brand_logo': logo,
             'brand_name': service.organisation.name,
         }
     else: