Many thanks Desk Driver and AOG-YYZ
I did pay by CC, but the total cost was only £32, after my compen vouchers were taken into account (that's why we're flying this rather circumlocutious route). No chance then of protection with the CC as total paid < £100.
We got a quote from bmi transferring at YYZ.... cost over £1,000 a skull ruled that out unfortunately. Perhaps cheaper deals available but a couple of grands worth of compen vouchers meant that flying with bmi was the only real option costwise.
You both seem confident that United will still be trading and your views have given me some confidence in that regard...thanks,guys
Many thanks once again.