There was some discussion on this group not so long ago about
promoting Sudbury Hill and Sudbury Hill Harrow as interchange
stations.

I was at Sudbury Hill the other day, during the week-and-a-half-long
eastbound platform closure. The posters at the station advised
passengers for central London to travel to South Harrow using a
westbound train then return on an eastbound. This would add approx 7
to 17 mins to the usual journey time. I didn't see any mention at all
of the Chiltern service from Sudbury Hill Harrow to Marylebone.

This seemed to me a bit uninformative - they could have saved some
passengers time by bringing the service to their attention and putting
a list of the Chiltern departure times on the poster.

This contrasts with the situation at Harrow-on-the-Hill during the
weekend Met closures, where passengers for central London are advised
and encouraged to use Chiltern rather than the LU replacement buses.