Your card is charged as soon as you make the booking. It can sometimes take a few days for the money to be claimed though, so it might not show up on your statement straight away but will most likely be a pending payment. Don't worry because once the booking has been authorised the money is earmarked so that when we are ready to take the money it'll be available and it won't be spent.
If you're not sure if a booking's gone through, you will get a booking reference number at the end of the booking process to confirm its gone through for you and you can always check the order history in your online account. As always, feel free to get in touch if there’s anything you're not sure about.