Mhm.... so my plan on driving it back on 3 old winters and a spare is in jeopardy a bit... as I don't have the old tire since it blew out.Sorry took a bit to come back to update.
Ended up being ok after a bit of back and forth with the agent and RP on the phone. Phone rep kept insisting that it needed to be on original or steel wheels and driveable but not on a spare tire. The agent in person didn't agree.
I told them "I'll go out and get the hand jack and swap the tire if that makes you happy, and drive it on a flat". Eventually phone rep said it was ok.
He apologized after and said, if it was me I wouldn't bother, but the system is going to ask me to put a note to show that I called if I report the spare tire being used.
All good in the end. 2 of 2 now gone.
I guess it'll be worth buying a used 16" winter tire to make it easier....