Our mk1 Jazz we passed on to our daughter has done over 170K, if it sounds and drives alright, I wouldn't be too worried mechanically. Full history is nice, ours came with a box file full of receipts, lovely. Check previous mot history here
https://www.check-mot.service.gov.ukfor anything suspicious, and look underneath if you can to see how bad the rust is, and it will be rusty at that age. Jazzes are pretty bomb-proof mechanically, but make sure the ABS warning light comes on with the ignition and goes out, listen out for droning rear wheel bearings, and whining coming from the gearbox as they are prone to gearbox input shaft bearing failure. Dip the clutch in neutral, and listen for whining or rumbling when you lift the clutch.
Ours had a clutch around 110K miles, but it was a driving school car for the first 100K, so that's not really representative. It's all down to driving styles, a clutch can last the car out with a careful driver.
Try to get the price down, 950 is a bit steep around here for a 54 plate with 160K on it.