It should be easy for registrars, or any company for that matter, to prevent this sort of thing happening.
In the event that anyone wants to change details in an account, the only way it should be possible to do that is for a phone call to be made to the current phone number listed in the account, to confirm if it's them requesting the changes.
I see the owner of that transworldleisure.com domain owns railsaver.co.uk which is registered through LCN, Who-Is for the .co.uk gives contact details as an P.O. Box number in Vanuatu.