tax treatment of a lease on a pub

Have a client who has paid £25k for 10 years remaining on a pub lease from the brewery as well as paying a monthly rental.

Was going to capitalise the lease and write off over 10 years at £2.5k per year.

But how is the £25k paid treated from a tax viewpoint?  What tax relief do they get if any and when do they get it?

Have looked around various references but cant find the answer.

Regards

Mark

PS happy crimbo.