Thanks guys. It's really tough getting anything to fit the upper body when your a big chap. I'm 5'10 and 19st very broad across the chest and shoulders.
Off topic but its a nightmare getting things like outdoors shirts etc.
I just found this one, which looks like it might be OK
http://www.intertent.co.uk/product_414-23-97_Vango-Nitestar-300-XL-Square-Sleeping-Bag.htm
EDIT
Maybe we should have a FAT KIT sticky lol
Ahh, this is something I know about
Get a bag that you like and get extension panels for it. Although it depends on how large we're talking, when it's cold i can fit into a nanok, if it's warm it kills me to be in it, i've bought XXL sleeping bags and all sorts but the one i use more than any other is my old snugpak black on black 2 with extension panels in it.
Some of the military bags are big as well. An alternative is to get one made for you, but that depends on how deep your pockets are.