Letting Agent fee to terminate equivalent to 14 months fees! do I have to pay?

Letting Agents

Spicer Haart want to charge the equivalent of 14 months fees to terminate their 'rent only' management contract (7%). I read the clause to mean FEES of one month's rent which would be fair.

I am ending the existing tenancy because the lead tenant of 3 vacated, and I'm intending to create a new tenancy with the the other two tenants on slightly lower rent.

This is what the agents say:
"Can you kindly confirm that you intend to take over on the 08/03/2022?
Please note that a withdrawal fee of one months rent +VAT is applicable to proceed as stated above, in line with our terms of business – please find the relevant clause below:

1. 3.23. terminate the contract following a successful letting of the property by us and the existing tenants remain in the property under either a statutory periodic tenancy or enters into a new fixed term tenancy agreement directly with you, you agree to pay a fixed charge equivalent to one months’ rent + VAT (provided that we are not in breach of the contract)."