Management company pet fees

[DaGuv]

I’m the landlord of a flat and my tenant wants to have a house cat. She’s a long term tenant and she’s great. I have no objections to the request. However the lease says I need written permission. I presume this is from the management company on behalf of the leaseholder. I wrote to the management company and they want me or the tenant to pay a £75 fee to apply to have the pet. Does this sound right? Seems extortion to me!