diff --git a/.gitignore b/.gitignore
index d19df2e94..12f77b15c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+queues.csv
+
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]
diff --git a/app/dao/notifications_dao.py b/app/dao/notifications_dao.py
index 7ebf9170c..f4ff2a24f 100644
--- a/app/dao/notifications_dao.py
+++ b/app/dao/notifications_dao.py
@@ -9,7 +9,8 @@ from flask import current_app
 from notifications_utils.recipients import (
     validate_and_format_phone_number,
     validate_and_format_email_address,
-    InvalidPhoneError
+    InvalidPhoneError,
+    InvalidEmailError,
 )
 from werkzeug.datastructures import MultiDict
 from sqlalchemy import (desc, func, or_, and_, asc)
@@ -477,7 +478,10 @@ def dao_get_notifications_by_to_field(service_id, search_term, statuses=None):
     try:
         normalised = validate_and_format_phone_number(search_term)
     except InvalidPhoneError:
-        normalised = validate_and_format_email_address(search_term)
+        try:
+            normalised = validate_and_format_email_address(search_term)
+        except InvalidEmailError:
+            normalised = search_term
 
     filters = [
         Notification.service_id == service_id,
diff --git a/manifest-api-preview.yml b/manifest-api-preview.yml
index 04b396388..a40990194 100644
--- a/manifest-api-preview.yml
+++ b/manifest-api-preview.yml
@@ -6,3 +6,6 @@ routes:
   - route: notify-api-preview.cloudapps.digital
   - route: api-paas.notify.works
   - route: api.notify.works
+
+instances: 1
+memory: 256M
diff --git a/manifest-delivery-base.yml b/manifest-delivery-base.yml
index c68d36965..2eaf380a6 100644
--- a/manifest-delivery-base.yml
+++ b/manifest-delivery-base.yml
@@ -24,6 +24,7 @@ applications:
 
   - name: notify-delivery-worker-database
     command: scripts/run_app_paas.sh celery -A aws_run_celery.notify_celery worker --loglevel=INFO --concurrency=11 -Q db-sms,db-email,db-letter,database-tasks
+    memory: 1G
     env:
       NOTIFY_APP_NAME: delivery-worker-database
 
@@ -34,13 +35,13 @@ applications:
 
   - name: notify-delivery-worker-sender
     command: scripts/run_app_paas.sh celery -A aws_run_celery.notify_celery worker --loglevel=INFO --concurrency=11 -Q send-sms,send-email,send-tasks
+    memory: 1G
     env:
       NOTIFY_APP_NAME: delivery-worker-sender
 
   - name: notify-delivery-worker-periodic
     command: scripts/run_app_paas.sh celery -A aws_run_celery.notify_celery worker --loglevel=INFO --concurrency=2 -Q periodic,statistics,periodic-tasks,statistics-tasks
     instances: 1
-    memory: 2G
     env:
       NOTIFY_APP_NAME: delivery-worker-periodic
 
diff --git a/manifest-delivery-preview.yml b/manifest-delivery-preview.yml
index d628e5fc9..2bbb3c0dc 100644
--- a/manifest-delivery-preview.yml
+++ b/manifest-delivery-preview.yml
@@ -1,3 +1,4 @@
 ---
 
 inherit: manifest-delivery-base.yml
+memory: 256M
diff --git a/manifest-delivery-production.yml b/manifest-delivery-production.yml
index 53c8d2f12..d2c2ba647 100644
--- a/manifest-delivery-production.yml
+++ b/manifest-delivery-production.yml
@@ -3,4 +3,4 @@
 inherit: manifest-delivery-base.yml
 
 instances: 2
-memory: 1G
+memory: 768M
diff --git a/manifest-delivery-staging.yml b/manifest-delivery-staging.yml
index 53c8d2f12..d2c2ba647 100644
--- a/manifest-delivery-staging.yml
+++ b/manifest-delivery-staging.yml
@@ -3,4 +3,4 @@
 inherit: manifest-delivery-base.yml
 
 instances: 2
-memory: 1G
+memory: 768M
diff --git a/scripts/delete_sqs_queues.py b/scripts/delete_sqs_queues.py
old mode 100644
new mode 100755
index bdbf6ff65..b167ce392
--- a/scripts/delete_sqs_queues.py
+++ b/scripts/delete_sqs_queues.py
@@ -1,10 +1,33 @@
+"""
+
+Script to manage SQS queues. Can list or delete queues.
+
+Uses boto, so relies on correctly set up AWS access keys and tokens.
+
+In principle use this script to dump details of all queues in a gievn environment, and then
+manipulate the resultant CSV file so that it contains the queues you want to delete.
+
+Very hands on. Starter for a more automagic process.
+
+Usage:
+    scripts/delete_sqs_queues.py <action>
+
+    options are:
+    - list: dumps queue details to local file queues.csv in current directory.
+    - delete: delete queues from local file queues.csv in current directory.
+
+Example:
+        scripts/delete_sqs_queues.py list delete
+"""
+
+from docopt import docopt
 import boto3
 import csv
 from datetime import datetime
-from pprint import pprint
-import os
 
-client = boto3.client('sqs', region_name=os.getenv('AWS_REGION'))
+FILE_NAME = "/tmp/queues.csv"
+
+client = boto3.client('sqs', region_name='eu-west-1')
 
 
 def _formatted_date_from_timestamp(timestamp):
@@ -27,15 +50,18 @@ def get_queue_attributes(queue_name):
         ]
     )
     queue_attributes = response['Attributes']
+    queue_attributes.update({'QueueUrl': queue_name})
     return queue_attributes
 
 
-def delete_queue(queue_name):
+def delete_queue(queue_url):
+    # Note that deleting a queue returns 200 OK if it doesn't exist
+    print("DELETEING {}".format(queue_url))
     response = client.delete_queue(
-        QueueUrl=queue_name
+        QueueUrl=queue_url
     )
     if response['ResponseMetadata']['HTTPStatusCode'] == 200:
-        print('Deleted queue successfully')
+        print('Deleted queue successfully {}'.format(response['ResponseMetadata']))
     else:
         print('Error occured when attempting to delete queue')
         pprint(response)
@@ -43,10 +69,10 @@ def delete_queue(queue_name):
 
 
 def output_to_csv(queue_attributes):
-    csv_name = 'queues.csv'
-    with open(csv_name, 'w') as csvfile:
+    with open(FILE_NAME, 'w') as csvfile:
         fieldnames = [
             'Queue Name',
+            'Queue URL',
             'Number of Messages',
             'Number of Messages Delayed',
             'Number of Messages Not Visible',
@@ -55,23 +81,19 @@ def output_to_csv(queue_attributes):
         writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
         writer.writeheader()
         for queue_attr in queue_attributes:
-            queue_url = client.get_queue_url(
-                QueueName=queue_attr['QueueArn']
-            )['QueueUrl']
             writer.writerow({
                 'Queue Name': queue_attr['QueueArn'],
-                'Queue URL': queue_url,
+                'Queue URL': queue_attr['QueueUrl'],
                 'Number of Messages': queue_attr['ApproximateNumberOfMessages'],
                 'Number of Messages Delayed': queue_attr['ApproximateNumberOfMessagesDelayed'],
                 'Number of Messages Not Visible': queue_attr['ApproximateNumberOfMessagesNotVisible'],
                 'Created': _formatted_date_from_timestamp(queue_attr['CreatedTimestamp'])
             })
-    return csv_name
 
 
-def read_from_csv(csv_name):
+def read_from_csv():
     queue_urls = []
-    with open(csv_name, 'r') as csvfile:
+    with open(FILE_NAME, 'r') as csvfile:
         next(csvfile)
         rows = csv.reader(csvfile, delimiter=',')
         for row in rows:
@@ -79,6 +101,19 @@ def read_from_csv(csv_name):
     return queue_urls
 
 
-queues = get_queues()
-for queue in queues:
-    delete_queue(queue)
+if __name__ == "__main__":
+    arguments = docopt(__doc__)
+
+    if arguments['<action>'] == 'list':
+        queues = get_queues()
+        queue_attributes = []
+        for queue in queues:
+            queue_attributes.append(get_queue_attributes(queue))
+        output_to_csv(queue_attributes)
+    elif arguments['<action>'] == 'delete':
+        queues_to_delete = read_from_csv()
+        for queue in queues_to_delete:
+            delete_queue(queue)
+    else:
+        print("UNKNOWN COMMAND")
+        exit(1)
diff --git a/tests/app/dao/test_notification_dao.py b/tests/app/dao/test_notification_dao.py
index a6b69cd24..dc0f3fc34 100644
--- a/tests/app/dao/test_notification_dao.py
+++ b/tests/app/dao/test_notification_dao.py
@@ -1772,6 +1772,20 @@ def test_dao_get_notifications_by_to_field_search_is_not_case_sensitive(sample_t
     assert notification.id in notification_ids
 
 
+@pytest.mark.parametrize('to', [
+    'not@email', '123'
+])
+def test_dao_get_notifications_by_to_field_accepts_invalid_phone_numbers_and_email_addresses(
+    sample_template,
+    to,
+):
+    notification = create_notification(
+        template=sample_template, to_field='test@example.com', normalised_to='test@example.com'
+    )
+    results = dao_get_notifications_by_to_field(notification.service_id, to)
+    assert len(results) == 0
+
+
 def test_dao_get_notifications_by_to_field_search_ignores_spaces(sample_template):
     notification1 = create_notification(
         template=sample_template, to_field='+447700900855', normalised_to='447700900855'