There seems to have been another of the periodic surges in 'what calibre' threads, with the usual passionate advocacy of one cartridge over another.
In fact, for every cartridge between .243 and .30-06, you can find at least two or three people utterly convinced that THIS is THE cartridge - and they will give detailed and ostensibly reasonable explanations for why.
It got me thinking: this really just seems to illustrate that for UK stalking, at standard stalking ranges, the differences between them are so marginal as to be objectively insignificant. They all work perfectly well, and the perceived differences are more down to personal conviction, individual ability and (maybe) variation in rifle and bullet construction.
To put it another way: how many people would even notice if you swapped their rifle for an identical one in a different chambering? I imagine very few - and even fewer would see it actually affecting their stalking.
If only your FAC simply said 'x number of deer legal rifles in the calibres of the holders choice'.