Service status page /status is generating a missing template warning

The following is appearing in our logs when someone visit the service status page of a service

> Theme hook page_header not found.

Eg. here https://www.brighton-hove.gov.uk/planning/update
(BHCC changes the url, but it is the status page for a service).

Also confirmed on the demo content at /adult-health-and-social-care/status
