Portmeirion is fatastic, you'll have a great time. Just watch out for that big white balloon!!!!

And remember, you are not a number, you are a free man!
Cant be much help with the waistcoat thing tho..... unless Moss Bros do a larger range? Or how about Burtons??? If you have an Officers Club near you, they might have some, I seem to remember they had some bigger sizes last time I went in there... not sure if they do smart clothes tho or just casual.
Dawn xx