Welcome to the forum Michael
Its not uncommon for the 350Z to need a clutch at that mileage as it may not necessarily be worn out but could have issues with the Dual Mass flywheel or concentric slave cylinder or both.
Retail from Nissan to replace the clutch, DMF and CSC is well over £2000 so this may be why the garage is keen to off load the car. We sell the genuine Nissan replacement parts at £1295.
You can also go aftermarket as mentioned, we are just about to announce a complete replacement kit from Xtreme Clutch that includes a single mass light weight flywheel, uprated organic clutch kit and their own designed uprated concentric slave cylinder.
The uprated CSC is a very important part as the standard Nissan item is a weak point and cannot cope with an uprated clutch kit.
If you want more information please get in touch