Hmm, well, yes, something like a piece of paper in the post, yes.

However, I think it's increasingly unlikely I'm going to go, as I've just found out that not only am I going to be on a BD flight that afternoon, I'm also going to be on an LO flight the next day... (Annoyingly, it's actually going to be held about 200yds from my office, but I won't be there...)

RSVP is due by Wednesday this week, and I'm allowed a guest. So, there may be a way of passing on the guest invite, should anybody want it...