For all applicants who are aiming to get a letter from someone known in UK as evidence of accommodation proof, I would strongly recommend them to read through sections 9.4 to 9.12 of
Chapter 9 of the Entry Clearance Guidance (ECG) available on the UKVisas website.
You will need the following from the sponsor:
1. A letter from sponsor stating his relationship with the applicant(s) and that the sponsor is ready to accommodate the applicant(s) in his residence/property. This letter should contain the following details:-
a) Size of property (e.g.- 2 bedroom house, 3 bedroom flat, studio etc.).
b) Number of people currently living there.
c) If possible, confirmation of a dedicated room for the applicant(s). Mandatory when couples are to be accommodated.
d) whether property is rented or owned.
2. Photocopy of sponsor's proof of income / salary slips / bank statements showing income credit - covering last 4-6 months.
3a. Photocopy of council tax bill for current year (gives the ECO an idea of size of property).
and / or
3b. Photocopy of utility bills - covering last 4-6 months.
4. If the property is rented, it is always better to include a copy of the tenancy agreement and permission from landlord allowing the sponsor to accommodate extra persons.
5. Copy of personal details and *current* visa pages of sponsor's passport.
Please note that reservation confirmation of accommodation in hotels / hostels / bed & breakfast lodges etc. for a week or two were considered adequate evidence by the Indian BHC during the HSMP days. And I have no reason to believe that these will not be accepted today, if proof of accommodation has become a requirement again. For applicants who do not know someone in UK who can sponsor accommodation, this is a perfectly viable alternative.
Hope this will put to rest most (if not all) doubts regarding accommodation proof.
regards