Just to note this Catch 22 is a little infuriating. They want to know that for sure we will return to Canada, but us returning to Canada is entirely contingent on our residency approval.
I'm sure as hell not moving home without him, and we'll have to country hop some more I guess if it's denied.
So I don't like that I would have to rent an apartment, sign a lease, with his residency up in the air. Does any one else think that's madness!?
I sponsored my husband, also a British national, and I too wondered how we would prove our intent to move back to Canada. We live in the UK and both work full time. We didn't want to find jobs or rent some place immediately as we had no idea if my husband would be even approved, or how long it would take. At the time it could take anywhere from 4 months to 8 months or longer. So for proof of intent I just wrote a letter stating that if he was issued with a visa we would at that time start to do things like look/apply for jobs, look for a place to live etc. I think it was about half a page long (there is only so much you can say about what you intend to do:). That was all we had for proof of moving back. My husband was approved for a visa after 3 months (though it was another 6 weeks before his passport was returned). I didn't have to worry about a bank account as I still have an active account in Canada. I guess, just be honest and tell them what you are planning on doing. If your mother could act on your behalf to do things for you (like renting a place etc) then it wouldn't do any harm to your application.
I should say that my husband is planning a trip to Canada in September to land, and to look for/do some job interviews and to find a place to rent. Then we are all (we have 2 children) going to move over in November. This is a few months after the hypothetical date I wrote in the intent to move back letter...but that is only because of a family wedding, otherwise we would have moved by the original date.
Anyway, hope some of this information is useful and good luck on your application:)