Checking... he says "quite a long time ago now," so that would almost have to rule out Secret Smile, since that was only a couple of years ago.

And given he says film rather than television program, I'm gonna concur with your guess about him referring to LAMAP.

I swear, sometimes these interviewers/hosts put him into the most awkward situations and he just rolls with it (worst I've seen yet would actually be the Big Quiz of the Year 2005, not Graham Norton). Such a nice guy.