Hi, I can highly reccommend these people
Stiles & Bates my best mate in the UK gets his exotic hardwoods from them (Purpleheart, Lacewood, Ebony etc) as well as other bits and bobs. They're based in Kent, just up the road from Dover but they do do a mail order service. (I think)
I've been to their shop and it's a gold mine and the wood they sell as lathe blanks is wax sealed at the end grain and is well stored.
Hope this helps.