I have also received the letter but have decided to complete the W8BEN form to ensure that any potential future tax (lol - will I ever sell?) flows through the correct channels - I don't want to end up with fiddly US tax stuff on my tax returns. Anyway, upon filling the form on the reverse, point 8 asks for the reference number - I have just emailed AST to confirm which number this is. Once they confirm, I'll then post the form off.
BTA Price at posting:
57.0¢ Sentiment: Hold Disclosure: Held