Hey Ian,
Sounds like you weren't kidding when you said your PO is a bit suspicious...Got the SASE I sent out to you back with the NIXIE message "Return to sender, attempted-not Known, unable to forward"
Seriously, how can they not find one of their own PO boxes? Anyways I was just going to resend to the same address and see if it goes through again. Figured maybe with the info you can see about tracking down what and where the PO's problem is. Looks like from what I can tell from the stampings it made it to at least zip 92159-41611.