Spoke to Colin on the day. I think he was a bit annoyed with the staff as his photoshoot was downstairs and he was signing upstairs and Sylvester's was the opposite. They made him get changed in a cloakroom with a window that wouldn't shut and by the time he got down there he was 20 minutes late.
Still a thoroughly nice bloke who took the time to chat with me about the Big Finish audiobooks.