They used to always force the CC at their unfavourable rate without giving any meaningful choice to the consumer (which is against Visa and Mastercard's rules for Dynamic Currency Conversion)
With their new website they do pretend to offer a choice, but the only time I've tried to use it it didn't work and my GBP card was debited in GBP despite selecting the option to be billed in EUR ( The rate they used to convert to GBP had a 3-4% spread which is annoying as if I was billed in EUR the charge would have been zero as the card used has no fee for forex transactions)