Faz,
to be honest your better off with the RPS kit and will be about the same price as OEM with VAT etc from nissan. I did mine before Christmas and got a local garage (Who owned a Z) to fity it for me.....Also, make sure you get an uprated pivot ball as well which are prone to fail..If you're doing the clutch a wothwhile extra while the box is off! I scanned teh forums for a week on advice for this job before i decided so have a good look around the forum and get some info...
I also replaced the slave cylinder (OEM) for an extra 50/60 quid which is also prone to leak with teh pressure of a new clutch plate!
I bought mine from Smithys Place and he was alot faster on delivery than Nissan too!
best of luck!
Damian.