I have a museum events guide for all the city musuems.  I noticed that there are a number of craft fairs that take place around my local museums and these are published in most council-related publications (so must get some good coverage).  It might be worth going to your local museum and picking up a guide (they are also available at libraries etc....  I would think if you called your local council, they would be able to give information too).

Anyway, there are a couple in Leicester in the run up to Christmas (both in very lovely & quirky locations - lol, both the following places have been investigated by Most Haunted):

Sunday 23rd November 11am-4pm
Belgrave Hall & Gardens (the most beautiful location)

Saturday 29th & Sunday 30th November 11am-4pm
The Guildhall Leicester (very old building)

Might be worth seeing how much the tables are at any similar events locally