You'll be hit with charges whatever way you do it.
If you pay using a nakit card then you'll likely get a poor conversion rate and foreign currency transaction fee - do they work outside Turkey now? Never used to, but then I've never tried recently so may have changed.
If you pay by bank transfer, you pay a fee and unless you tick the box to pay ALL associated fees, the recipient is likely to be charged also. Do it from a GBP account else there are even more charges for currency conversion.
JF