This is from MSE.com - very reputable site.
What if I've booked a holiday for more than six people?
It's worth noting that the new rules won't affect single households or support bubbles of more than six people. So if you have a UK trip booked with just members of your household or support bubble, this should still be able to go ahead even if there are more than six of you.
But if your trip is for two households with more than six people in total, you now won't legally be able to gather or stay together in the UK – whereas previously, for example, two families of four would have been allowed to go on holiday together.
In this case, it's best to speak to your holiday accommodation provider and explain the situation, as some may offer flexibility or refunds. But if your holiday provider refuses, whether you're legally entitled to a full refund isn't entirely clear-cut.
When we asked the Department for Business, Energy and Industrial Strategy about consumers' refund rights in this situation, it pointed us to guidance from the Competition and Markets Authority (CMA), which says that consumers should get a refund if they cancel or can't use a service because of Government health measures.
As the new six-person rule is a legal restriction (unlike the current rules on households staying together, which are guidelines) and consumers could face a fine if they break the law in order to use their holiday booking, the CMA guidance suggests they'd be owed a refund.
But it's important to note that CMA guidance isn't a definitive interpretation of the law, and this is a new scenario which hasn't been tested – so while you can point your holiday accommodation provider to the guidance, complain to the CMA or even pursue legal action, there are no guarantees as to what the outcome would be and whether you'd get a refund.
This situation is made more difficult by the fact that in some cases it could be possible for some consumers to make use of the bookings, for example, if six of the planned guests went on the trip.