If you're looking to buy film for a film camera and have the film developed, here's where people have recommended!
Map
by far the most recommended. they're also happy to help fix your camera if needed
Cameratiks
Does development
A + M imagery
Can buy film but don’t recommend development
Boots: Beauty | Health | Pharmacy and Prescriptions
I’ve bought film and had photos developed here! I think they moved locations
Agitate Gallery
Film and developing
Wex Photo Video Edinburgh
Recommended for film and development
Kodak Express
You can drop off in Edinburgh at Stills (in Old Town) or mail in by post - cost 8 GBP
Gulabi Photo
Based in Leeds but you can mail in film and get it back in a few business days. They email you the online digital scans and mail you back the negatives