HELP with letter for Un-married partner visa Application Forms

My partner will be apply for the Un-married partner visa. Once we get to the UK we will be staying with friends until we get a place I have read we should get a letter from them to send of with the Application Forms agreeing that we can stay with them.
What should they write in this letter ?
Thanks

They need to show that they own or legally rent the property.  If they are renting, they need to show that they are permitted by their landlord to let you stay there.  They then need to provide a document to show how many rooms there are in the property, in order to show that it will not be too crowded.  The letter then needs to say that they are happy for you both to stay there for as long as you like, and that you will have your own room.


Victoria

thank you.