The only fair I do now is the Art Deco Fair at Eltham Palace. This is an English Heritage site at Eltham. Full details are on the Eltham Palace/English Heritage web site. The fair takes place in May and September.
This year the fair takes place on - 10th and 11 May 2014 and ? September.
The entrance fee includes the Palace, the Medieval Hall and the Gardens. The fair is in the Medieval Hall.