I would recommend readng through
Maintenance and accommodationsection of the Entry Clearance Guidance (ECG) available on the UKVisas website.
You will need the following (from the sponsor):
1. A cover letter from sponsor stating his relationship with the applicant(s) and that the sponsor is ready to accommodate and / or ttake the responsibility of maintaining the applicant(s) during his/her visit to UK. If accomodating the applicant in your own residence, this letter should include the following details / information:-
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.
(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).
2. Photocopy of sponsor's proof of income / salary slips / bank statements showing income credit and availability of funds (if sponsor is taking the responsibility of maintenance) - covering last 4-6 months.
3a. Photocopy of council tax bill for current year (gives the ECO an idea of size of property).
or
3b. Photocopy of utility bills - covering last 4-6 months.
4. Copy of personal details and *current* visa pages of sponsor's passport.
There may be a requirement to submit documents showing evidence that EC applicant(s) has ties with home country and will return at the end of the visit (e.g.- employment letter, savings held or investments made, home ownership etc. etc.).
In OP's case, skip (1) & (3) and include proof of hotel accommodation for the duration of visit with the EC application.
Letter from sponsor - in original.
UK documents (sponsor's) - photocopies will do.
Passport (sponsor's) - photocopies will do.
Home country documents (applicant's) - in original
regards
