If you don't have a visa or mastercard then you can't pay except by cheque which incurs the 17.5% VAT charge. I don't understand why this is and will make a fuss as I have never had a problem paying for things with my maestro debit card before and I'm really irritated. I'm now waiting for my mum to get here as I think she has a visa card and she will pay it for me. But just be warned if you're trying to get the HEors discount - make sure you have someone who'll lend you the money and let you pay with their visa or mastercard if you don't want to pay extra! (apparently it can be a debit or a credit card, just only visa or mastercard ones).