http://beefayre.yaldingbeekeepers.co.uk/
I am going to this next weekend (May 11th 2013), taking one of my little boys to enjoy the attractions and then seeing what I can get at the auction.
It was good just as an auction when I went a couple of years ago, now its bigger and seems to be attracting a lot more attention.
Its not far on the other side of the Dartford crossing if I recall correctly.