[Shooby doo]

Please take special note that any delay or disruption to any part of your holiday does not automatically entitle you or anyone else in your
Booking Group to cancel and claim a refund or other compensation unless it is impossible for us or our suppliers to perform the Booking
contract. If the Package or travel services can still be provided any subsequent cancellation by you will be treated in accordance with Section
12 below. If, however, we determine that it is impossible for your Booking contract to be performed then Section 9a below will be applicable.

So it really depends why you can't go IYKWIM, in theory as long as WDTC can perform their part of the contract then it is you cancelling. It could also be argued that if you bought now then you are also aware of current restrictions. What I think that they would do is give you a ticket extension but all that being said who knows at the minute
SD