Please note that only your second paragraph is relevant for WGT ProShop purchases. All the rest, the numbers, etc., is irrelevant, because those things talk about you receiving money, not about your sending money to WGT.
So, what you posted simply confirms that there are PayPal fees in Great Britain for sending money via credit card-funded PayPal, but it doesn't specify what the fees are. I would approach PayPal's customer support to inquire about this; they're usually prompt to get back to you.
Also, it's important to remember different fees apply to different countries / currencies in which PayPal operates, and that there are various types of PayPal accounts. Some of the account types need to pay certain fees, and others don't.