It is a shame those days are long gone... I hear a lot of people justifying their use of light rifles by dropping his name... for most people, thats all they know about him, and that he used a light rifle to kill many hundreds of elephants. The only reason he lived to give the 7x57 and the .256 MS the fame they now have in Africa was 90% his almost superhuman shooting skill, 10% super deep penetrating bullets. He once shot 10 rounds from a Enfield sporter into a herd of fleeing zebra, dropping 10 animals in quick succession (likely neck shots on a zebra running 30-40 mph) from a range varying from about 30 to about 120 yards, to basically establish for the Karamojong natives that he was not to be messed with. They, understandably, backed off. I'm a history buff... can't help it.The man who gave fame caliber 7x75.
I think the 7x57 is a great round, but i wouldn't poo poo the .270 either, ballistically, it can easily keep up with the 7x57 and surpass it. Especially since the former has approx. 10 extra grains of case capacity.
To the OP, If you already predominantly use a .270, I would use it! That said, all three have 95% the same capabilities. Pick one and hunt! load up some TSX's and go stalk something! As a side note, Is it terribly difficult to get reloading components in Scotland or the UK? Are powder, primers and bullets fairly easy to find and are they something you can buy over the counter or do you need a license?