His sister, Jane, has written:
We have just come back from Cambridge, having gathered all my siblings to celebrate Mark's 50th, or, as he says, Chris' 52nd. Great catch up with all.
Well, there you go. These people who were toddlers only a little while ago are now turning 50 and 52. Scary.
I've sent an email to all those on my address list to see if there's any interest in another family reunion. A small amount of response so far, but some response at least!