Hi Alex, We very clearly state this amount in the document that you sign before you pay any money over for referencing and it is right there in black and white and listed as a separate line item on your pre tenancy form. This cost is to cover administration charges to the company involved in tenants who do not return the property in the agreed condition. This amount quite often does not come close to covering the administration cost involved at the end of some tenancies. In the majority of cases we work with the tenants to try and get issues resolved and looking at you example of a key.... well we would give you the opportunity to get this cut yourself and so have all your admin fee refunded.