> Buckwheat is not wheat, soba noodles are based on buckwheat.

Whilst you're correct about buckwheat, just about all soba noodles that I've seen here in the UK are predominantly wheat based (I'm gluten sensitive, so have read a lot of product labels).

When looking for gluten free noodles in Asian supermarkets, I've only really found ones that are rice based with some rarer sweet potato vermicelli varieties.

Edit: after a brief search, I have found some Clearspring 100% buckwheat noodles which I shall have to find and buy. They also sell the more usual wheat and buckwheat version of Soba noodles.