The rent review will be covered in your current lease. Your first step would be to let your surveyor have a copy of the lease and your landlord’s letter. If the rent is due for review the basis of review will be set out in the lease. Your surveyor will be able to advise you on the current market levels of rents in the area and will be able to negotiate with the landlord ot make sure you do not agree to any unjustified increase in rent. If agreement cannot be reached, it is usually possible to refer these matters to arbitration.