Have you tried using G2A? 10k GE starts at about £17 there.
Plus wont you have to pay a service fee for currency exchange to your bank?
I tried using G2A to get one of the 10kGE Nvidia promocodes and they turned down all of my cards for no reason (every detail was correct and I had enough money each time). I currently have £47 on my own personal card that has been sitting in refund limbo for the past week thanks to how Paypal does the payment process. One of my family members let me use their card to buy through the Russian Gaijin method and it worked first time and I had bought the premium Pershing within five minutes. Compared to all the hassle I've gone through over the last week I couldn't care less if my bank charged me a 50% currency exchange fee as long as I actually got the bloody thing I paid for.
Besides, the 10kGE codes from G2A can only be used once per account, they're promo codes that Nvidia gave away with some of their graphics cards.