Anything PH-y going on in London 16/17/18 December?

[GreyGray]

Mrs GreyGray and I are going down to London the weekend of 16/17/18 December. Does anything know if there is anything on that might be interesting to go to - show/rally/auction? I realise it's a bit in advance but I'd like to get something pencilled in before the entire weekend is filled with Harry Potter studio visits and wandering around Harrods.

Cheers
G