I've been looking at the posters behind the charabanc to see if any of those contain any clues and have been able to read parts of a few of them:
- The ones one the far left are unclear, but the next two read "Evening Technical Classes".
- The next is for "Players Country Life" tobacco and cigarettes.
- The next is for "Ironclad", but I haven't been able to find out what that was (apart from a type of ship).
- Then something for bottles of "something or other", possibly beer or lemonade. Only the top parts of the lettering are visible, but it could read "T---T'S".
- Finally to the two on the right; the top one is unclear, but the one below may hold the answer. It seems to say "---AKEFORD, KURSAAL".
If that is correct I'd say the location is almost certainly Southend-on-Sea.