On [date] I stayed at your hotel for [number of nights] in room [number]. As I mentioned to your receptionist at the time, the accommodation was unsatisfactory in the following ways [describe].
When I asked to be moved to another room, I was told that this was not possible; nor were the problems rectified.
I have contracted with you to provide me with [details].
These were not provided with reasonable care and skill because [give details of problem].
It was an implied term of our contract that the accommodation provided would be of a standard of cleanliness and quality reasonably to be expected from this type and price of hotel.
It's also an implied term that the service provided would be done so with reasonable care and skill as required by the [Supply of Goods and Services Act 1982/ Consumer Rights Act 2015.]
Therefore, you are in breach of contract.
As such, I am legally entitled to receive compensation from you. In consequence I am claiming the sum of [£xx set out amount and how it was calculated].
I require your response to this letter within 14 days