you're looking at about �3k tops according to Glasses Guide. I wouldn't bother looking at Parkers - it's not a recognised guide in any part of the industry as you can buy it from WHSmith!
Any dealer worth his salt will use Glasses Guide, and it's fairly accurate if you compare it on 90% of cars on Autotrader (throw it out the window for Scoobies, Cossies, etc)