Yep sorry should of mnetioned that. It is already set to GBP, there is NO other options in the dropdown menu as I only have GBP published. So I don't know where it is getting the euros from.
If the displayed option is on, the prices will be displayable in euro on the front end but customers won't be able to purchase in that currency and the order will be done in the store's main currency.
You said you had the Euro unpublished and nothing about the displayed option, which is why I asked you that. Now that you're saying everything is set up correctly, I can only think of a session issue. I checked again your website URL and I see your prices in GPB. Maybe you should clear the cookies of your browser to see the prices in the good currency ?
On your link, I only see the GBP price so that means that you still have the EUR selected in your session on your website front end and the system converts automatically the currencies. An easy way to remove it will be to login and logout from your front end.
