The clutches on Zeds have been known to go twice with that kinda mileage ...
My Zed has had a new clutch at 28k Miles according to the service history
I wouldn't worry though unless you feel the clutch slipping while driving ... I think I read somewhere that if you can pick up from a stand still in 4th gear your clutch still has some life left in it ...
Anyway there are lots of options available if you do need it replacing ... They are usually around the £300 mark, and it's probably a good idea to also check your flywheel at the same time ...