Thank you. There is no basis for the agent to request new fees to be paid. Agents rarely seem to have a very good understanding of contract and tenancy law, but this agents approach appears to be a simple attempt at profiteering by attempting to charge fees for work that has already been carried out.
The best approach to such changes is by way of a simple deed of variation and if the landlord is willing to release the outgoing tenant from the tenancy (he doesn't have to) a release clause in the same deed. However agents rarely employ lawyer to prepare their tenancy agreements prefering to make what often amounts to a hash of them themselves. As a lawyer will very unlikely be involved, the agent could rather than a deed just simply ask the new tenant to sign a new agreement along with the remaining tenant - there is no need to change the dates of the tenancy. This is not good practice but the courts could clearly infer what has happened in the event of any dispute. This is broadly what the agents propose to do though they the requirements that they extend the tenancy and recharge all the admin fess is unreasonable.
Since your daughter and the other tenants do not require any changes to be made, in many ways this is not their problem other than the fact that the landlord can pursue any tenant for the outgoing tenants rent if she doesn't pay and in that sense it could become their problem if the outgoing tenant simply stops paying rent, though the remaining tenants have a claim against the outgoing tenant if she does not pay what she is required to to pay under the tenancy. This notwithstanding, the remaining tenants can simply take a position that this is not their concern and that they will not agree to any extension of the tenanc beyond its current length and wll not pay any further referencing checks to the agent and leave it to the outgoing tenant to negotiate better terms and pay and administration costs associated with her request to substitute a tenant. If the agent refuses to cooperate the remaining tenants can simply refuse to sign anything to alter the tenancy and advise the outgoing tenant that she must continue to pay the rent in the meantime and that they will make a claim for any unpaid rent from her if they are forced to pay such rent on her behalf because the landlord chooses not to pursue her personally.
If the agents to not agree to waive suplicate admin fees and the requirement that the tenancy is extended, neither of which there is any legal basis for, then the outgoing tenant can make a complaint to the agent and then refer that complaint to the Property Ombudsman service which the agent is required to be a member of free of charge and claim compensation for any loss she can show she has suffered because of the agents unlawful position but this would be an issue for the outgoing tenant rather than for the remaining tenants.
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