18-20K miles would be average for this age, so it's well over, if the alloys are repairable it's about £50 a wheel, year's tax is another £150, tank of petrol £40...given the age have you checked the tyres too - it's another £100-150 a tyre if they need changing any time soon...
..so £9K is not really that huge a discount off the cost of a new car when you add it all up especially as you can buy a brand new one for £10.5K from Archers of Ashby in Leicester, and from sites such as Autoebid, as it's a finance deal i'm sure the extra money can be stretched and is worthwhile...
M