The only weakness with the standardisation sheet is it says it is not legally binding (mine does I assume they all do). I would certainly use it as the first line of attack but we need additional arguments as well just in case...
The bank might be more receptive to an argument that proved we should get the rate applicable at the date we actually broke out of the fixed term because it would remove people like S2K from the picture and prevent additional floodgates opening for them. My understanding is that while the applicable rate in late 2008/early 2009 was not as low as the standardisation sheet it wouldn't be the worst and certainly a lot better than 3.3%
The bank might be more receptive to an argument that proved we should get the rate applicable at the date we actually broke out of the fixed term because it would remove people like S2K from the picture and prevent additional floodgates opening for them. My understanding is that while the applicable rate in late 2008/early 2009 was not as low as the standardisation sheet it wouldn't be the worst and certainly a lot better than 3.3%