I acquired a Hunka not sure what size it is but its in black from a Foaf who reckoned it was too big (and not waterproof coz of the entry hole) so might be an XL.... how do you tell?? I can post a pic if you want.
I have enough bivi's so was intending of disposing of it but wanted to give it a whirl first. Not sure when they'll be back in stock with Alpkit but would guess that this one will be available the week after Easter weekend.
Are you based in London?