I can't find the board about this, but I just had to recommend WARWICK CASTLE. We took our boys (2 and nearly 4) yesterday, and it was fantastic. The staff went out of their way to be helpful and friendly, and answering a 4 yr-old's questions. There was endless entertainment and amusement for two little boys dressed in their knights' tabards. (Under 4s are free, and we also had a two for one offer from Tescos, so it was a bargain too).
Does anyone know where I can buy small (cheap) plastic knights? (for a castle they already have).