Now, after a needlessly provocative thread title

What websites can I use to buy wood from for a potential build in the UK? I've looked high and low and ebay seems useless

Thanks for any help
Say no to drugs, but drink is good...
did you try googling "uk luthier supplier"

tonetech \
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Luthier's Supplies, Tonetech, Craft Supplies... Timberline are also good, just a regular timber supplier but the owner builds guitars and seems quite happy to help out on any project requirements
I can vouch for Luthier Supplies and Timberline, bother brilliant. Craft Supplies have had a downfall of quality (Of which I can confirm), but I hear they've gotten the game together again.
if all that fails, there are a few eBay stores that I remember browsing through.
Try something old tech like yellow pages and look up timber merchants, go for ones that list hardwoods. There are probably several within driving distance. Any of these will be used to providing guitar sized pieces and will let you rake through and select timbers and advise you as they often provide this service for joiners. If not I think one of our local merchants Yandles of Martock do mail order.