I looked back at the email that I received from BA regarding '
Congratulations, your Companion Award eVoucher is here'. When I clicked on the 'Book now' it took me to the UK website and my companion fare worked! It still doesn't work from the Canadian website.
Here's the link.
https://accounts.britishairways.com/...nF0emRiUHI0bnI
Cheers
Don