Hmm, all very curious. This is a new one on me!
Graham, I note what you say about Infrared codes 1 & 2, but I know nothing about this. Would like to see what happens if I change mine, but I don't know how or what it is on now. Is there something in the manual I have missed when I had a search just now?
Edit: I have found it (a Google search brought up a post by Barry, reposted by Graham) and I have changed from Code 1 to Code 6. Will wait and see what happens for a while.