Other guests are still to be confirmed by SciFiCollector, but it seems a great way to get an autograph. As they explain it:
Put simply, buy a qualifying item on the day and have one from your own collection signed for FREE. There’s no admission and no charging per signature. Qualifying items are generally prints, stamp covers or DVD’s being launched on the day.
Tom and friends will be appearing at The Stamp Centre on Thursday 23rd September 2010 from around 10 AM – if you can head to 79 Strand, London WC2R 0DE where the Fourth Doctor himself will be meeting fans and no doubt celebrating the release of Demon Quest!