You're in England?
Damn you should have the easiest access to malt (e.g. Maris Otter) and hops (e.g. Goldings and Fuggles) than anyone.
Is there nobody that sells to homebrewers really?
I'd check this forum:
Mainly American homebrewers on there, but I'm sure there are English ones as well.
Or sheck with CAMRA, they should know who sells on smaller scale to homebrewers too.