https://www.parkers.co.uk/honda/jazz/hatchback-2008/14-i-vtec-es-5d-cvt/105/free-valuation/ probably in the right ballpark considering the mileage. Ebay completed listings is another source of valuations. But then if like me you keep a car for any length of time, paying say £500 here or there is irrelevant a few months/years down the line, having bought a 'good' car is more important, to me anyway.
It looks like a cracking motor and if that 12 month warranty is included then its well worth a look.
Personally I think the Jazz is a great car, likely to be completely reliable and dead easy to service.
John
If you need it, make sure they are not ripping you off with the finance. At present interest rates are next to nothing. The figures provided in the advert would indicate interest at around 20% over the four year period.