Hi @Stuart415 !
I am a host in Tenerife with an entire place.
However, I'd like to share with you the information I recently obtained from the Canarian Vacation Rental Association (ASCAV).
The regulation in force in the Autonomous Community is the Dec. 113/2015 which initially banned the rooms. After going to court, it declared that rule unconstitutional, so the rooms are allowed, as a general principle 👏
Have a look to these first notes:
1. You must enter the page of the Government of the Canary Islands (sede electrónica del Gobierno de Canarias).
2. Complete the Activity Declaration (Declaración de inicio de actividad) model and when asking for cadastral reference you must indicate the number and, specially indicate that it is a room.
3. If you have more than one room listed, remember that each room must have its own registration number.
I hope this information helps you.
However, keep in mind that when it comes to regulations, it is always better to check with official sources (Cabildos and Town Halls - Ayuntamientos) since the information may have changed.
All the best!
Daniel.-