I've used these a couple of times, http://www.acefoam.co.uk/contact-us/ And they deliver. But agree with #vanorak, just google it
I got mine from Schofields, but as above you can get it from just about anywhere. Need to get the right density, tho' Top tip: if you need to cut it, invest in a nice new bread knife - works a treat!
Thanks for the replies. I'll have a look at the two companies suggested. The fact they can deliver is a bonus as I haven't been able to find anywhere local.
I used Ace Foam for replacement foam for my westy seat/beds too. They were really quick, pretty cheap, and they delivered. Nick...