Congrats!
As others have said, it looks like you'll need to get a CAD draft.
I think that like me you're in the UK, so you'll need to approach a bank for this. They only get foreign draft's for existing customers, and I am with HSBC and Nationwide. I tried HSBC first and got no joy there, but fortunately Nationwide said they could do it for me. From my conversations in the HSBC it looks like Barclays would be a quick bank to choose if you have an account there.
If your bank(s) can't do it then you'll need to give someone like Travelex a call to see if they can order you one.