There are changes to bus schedules and numbers in the Sidmouth area, effective from 8 May 2016.
Services 52A and 52B (Exeter to Seaton and Honiton) have new routes and are extended to serve as far as Lyme Regis. The new route numbers are 9 and 9A.
Services 52A and 52B from Exeter and Honiton no longer exist.
There is a new X52 service operated by First Group which supplements the altered X53 service. Basically the X52 and X53 operate as a pair of routes the X52 serving Exeter/Seaton/Bridport and the X53 further east.
The new X52 has nothing to do with the old 52A and 52B routes.
new 9 and 9A service, frequent buses from Exeter to Sidmouth
Bus timetables for Jurassic Coast services including X51, X52, X53, X54 and X55 can be found on first group website.
First Group website for X52 X53 etc.
A useful UK travel aids is traveline.info
There are dozens of apps of course.....