I photographed the last night of Nick Mason's UK tour last night. On the merch stand (and the tour starts in Europe this weekend then goes to the USA), they have a small number of items signed by Nick - some really nice posters and a drum skin. Not cheap, but authentic and I had a good chat with the guys there and indeed looked through all of the posters before picking mine out. They aren't signed by the rest of the Saucerful of Secrets band but Guy Pratt's book is also available signed. Apparently these items can be purchased online too but the merch guy didn't know the website address. Posters were £50 signed, the drum skin is £65.