It's just additional charge comes from the bank because of the currency conevrsion

There should be an option to pay in £ through your settings and via the main page. Is it not available for you?

As a suggestion, I had this with my bank for a while, even paying in £ as GOG is in Poland. I use paypal now and it goes through and I don't get the charges from the bank.

The US Dollar is the world's reserve currency. What this amounts to is, anything other than polish money spent gets converted to dollars and into the other currency, whereas before people converted through gold bars. At the end of the day, you should be able to pay anyone using almost anything. Just keep XE handy.

For anybody else's future reference: hover over your username in the nav bar across the top of the screen, then hover over "Language & currency" in the resulting dropdown, then select the desired payment currency and/or site language (not forgetting to click "Apply changes" afterward, if necessary). This is available from pretty much every page on the site (apart from the Support subdomain), unlike the options at the bottom of the page, which are only available in the store sections (front page, product pages, promo pages, Connect page, probably a few others).

The bastards at my old bank (a huge multinational that probably has trillions in assets) did this.

My new bank, a local credit union, has NO foreign transaction fees LOL. Just in case anyone wonders how the big guys get (and stay) big... ;)