As Olduser says, the MOT history will reveal how the car has been looked after (or not .... ). All you need is the reg number and go to the DVLA site.
Well worth finding a few similar vehicles advertised and check as many MOT histories as you can to see if there are any regular faults, stuff like corroded brake lines or leaking shocks etc can be troublesome and/or pricey. Most MOT fails/advisories are mundane stuff like lights/wipers/tyres/windscreen cracks etc.
I don't know what afflicts the age of Jazz you might be looking at, generally they are probably less troublesome than many other similar cars but every one is individual and depends what sort of life it's had.