Due to my circumstances (NB: not these ones!), I've been purchasing quite a lot of tickets from BA.com which actually start in the Eurozone. BA.com insists on pricing these in EUR (no huge surprise there) - this didn't used to be a big problem, but now I have the BAPP Amex (the UK version) it means if I pay with it, I get hit with a surcharge due to it being classed as a foreign currency payment and an exchange rate which may not be brilliant.

So, for instance, a recent ticket bought from "BA.com GERMANY" shows on my Amex bill as:

Foreign Spend Amount: 320,70 EUR
Commission: £7.61
Exchange Rate: 1.2604

Now, I'm earning Avios on that which offsets some or all of the commission fee, I've no idea what loading there was on the exchange rate (sure there is some...), but I'm wondering whether I'd be better going to an OTA in the UK who could price trips in GBP even for trips starting in the Eurozone?

What do you all do?