It really makes no difference as you'll have to pay tax one way or the other.
If work give you the 75 quid in your pay, you'll be taxed as normal and end up with around 40 in your pocket.
If they pay the fees for you, you'll end up with notional 75 added to your salary as BIK and end up paying the same tax on it.
There might be a benefit if you get a discount for corporate membership but as far as tax goes, they get you either way.