Originally Posted by
sigma421
The only risk on that is availability disappearing. If you're travelling at a popular time, I wouldn't leave it quite that long.
That shouldn't matter, if BA cancelled the flight then reward availability isn't required to move them to a new flight.
I would call up and ask what the options are - having looked to see what your preferred option would be in advance. Don't accept anything you're not happy with as you won't be able to change again.