Do you really need all of that cumbersome bureaucracy?
You can't plan for every eventuality, and this is a pretty exceptional situation. I don't remember another GP being cancelled, I remember the Inters being cancelled a few years ago due to bad snow at Newbury.
As far as I can see - there's sufficient mandate in the rules to cater for this situation :-
The BFTA reserve the right to vary the 7 nominated events at any time
That's in the rules at the moment, and that's a very broad statement that would allow any of the suggestions in this thread to be implemented under that mandate.
Isn't it enough to say - sometimes shit happens, but when and if it does, the BFTA will look at all the options and come up with what they feel is the most sensible solution.