I'm thinking that a fandom walk such as the Sherlock Holmes walk? I have been on this and would highly recommend it - anyone not sure of the fact it's 2 hours can be reassured that I completed this 4 weeks after I'd broken my foot a year ago and I managed the gentle stroll with ease. It's £12 each and we could then go on to eat somewhere?
Alternatively if anyone else would like to suggest something I'm happy to help organise it - there are other walks on that website.
Thoughts.... ideas welcome.