What is a preauthorisation charge?
When making a booking a pre-authorisation charge is taken against your credit card to ensure that the payment card is both valid and in credit. This charge may appear as a pending transaction on your internet banking, PayPal account or credit card statement.
The pre-authorisation is temporary and will be released within 5-10 working days. The money doesn't leave your account, it's just a hold to ensure the credit card is valid and may be charged in the event of any incidents, fines, damage etc.
When the pre-authorisation is released, you won't see a credit of the amount going back into your account. Instead, the pending charge disappears and the funds become available to you again.