It's probably still more efficient (both money-wise and GHG-wise) than growing bananas locally in UK; now that would need a lot of extra energy; but on the other hand it would be more efficient to eat food that normally grows locally in your climate instead of bananas.
Ofcourse that's true, but no-one is (or at least should be) eating multiple kilos of bananas, coffee and chocolate. They are not a staple food like meat and potatoes.
All I am trying to say is that in the total carbon footprint of a person, they account for a miniscule part of the whole, and that things like a well insulated house, transport, etc. will be vastly more important
It's probably still more efficient (both money-wise and GHG-wise) than growing bananas locally in UK; now that would need a lot of extra energy; but on the other hand it would be more efficient to eat food that normally grows locally in your climate instead of bananas.