Resolve duplicate mapping
Merge pull request #338 from rjc123/newmappings

Resolve duplicate mapping
Second use of automunge
Merge pull request #339 from rjc123/newmappings

Second run of automunge
Make it clear what migration we're talking about

Reducing cognitive overhead is good.
Merge pull request #340 from alphagov/clarify_still_to_migrate_filename

Make it clear what migration we're talking about
Resolve zendesk https://govuk.zendesk.com/tickets/278292