Hello again Gillian — I’ve edited this reply as I’ve since put together a comprehensive guide on how all this works and what you need to do as you’re not the only one confused! (even got ME going for a bit and I deal with this stuff routinely!). This answers all your questions:
Hope that helps!
Here’s the original response:
Hi Gillian! I’ve been dealing with finances and tax for many years. Although based in the UK I have pretty much had a W8 on file since the nineties as I have always had some sort of business interest there. I got the same email last night and, to be fair, it’s not brilliantly written — even I, as a guy used to dealing with tax, had to look at it several times before I worked out it wasn’t overruling the treaty agreement!
Anyway, glad you added the amendment at the bottom of the piece and are now a bit happier with it. Make sure also you are claiming everything you can against tax, here’s some pointers: (this is UK law but the principles will apply in Canada also)
How to Protect Your Writing Earnings from the Tax Man
What you can legally do to keep it safe
(and why anyone would vote for Trump is beyond me. That said, here in the UK we’ve got our own problems right now — Brexit anyone?!!)
All the best