Great suggestions above. Local vets are a good place to start as they will know of the reputable boarding places near you. If there is a local reputable rescue near to you they may offer boarding, too, or be able to recommend boarding for you. Alternatively you have the option to have a pet sitter come in a couple of times a day to tend to them.
My own piggies go to a small pet boarding hotel when we go away and they have always been very well looked after there.
If you are holidaying in the UK it may also be worth seeing if your accommodation would let you bring them with you. I know that some rental cottages will allow this.