Admin Fee can be specified at commencement of the tenancy agreement An admin fee covers costs for minor damages and to maximise your returns why not think about charging an administration charge? This is a charge for starting the tenancy, after all it is common practice for Agencies and it is legal so then why not you?
Some other charges you may wish to claim from the prospective tenant are to recharge the referencing (see Credit check) and the inventory charges and consider the cost of these:
Rent Smart Wales - Landlords Watch Out
Immigration Act revised 2016 should a landlord or letting agent fail to ensure ALL tenants/occupiers have a righto reside for the duration of the tenancy then they may be fined £3000 for each breach. The Secretary of State may instruct the landlord to remove such persons without the need of a court order by way of reasonable force
Labour market enforcement - restriction on illegal migrants to work. A labour market enforcement undertaking (an “LME undertaking”) is an undertaking by the person giving it (the “subject”) to comply with any prohibitions, restrictions and requirements set out in the undertaking