@Andrea6481 I AM WRONG>>>>>>> Or at least I might be. It depends what sort of guests you are hoping to find via Airbnb.
I found this on Visit Britain's website:
In order to be an HMO, the property must be used as the tenants' only or main residence, and it should be used solely or mainly to house tenants. Properties let to students and migrant workers will be treated as their only or main residence, and the same will apply to properties which are used as domestic refuges.
Therefore, holiday cottages let to families or other groups of people living together as one household for a holiday, who have a main home elsewhere, are not HMOs.
Where winter letting to groups of people who are not related is taking place, the premises may well be considered to be an HMO and you should seek advice.