How much can you knock a dealer down on price?

[SteffenFreund]

Hi,
I was wondering if someone can give me a idea of what would be a reasonable figure to expect to knock a dealer down on the price of a (expensive) second hand car?

I am looking at spending £19-20k buying a BMW 330CD, would sort realistic of price do you think I could expect to get the following for:

BMW Main Dealer:

Model: BMW 330Cd 2993 cc Sport CoupPrice:£21,750
2 Doors, Manual, Diesel, 32,280 miles, Titanium Silver, Anth Alcantara/Cloth, Elec Fold Exterior Mirrors, Lumbar support - fr seats, Multi-func. Steering Whl, Tyre Puncture Warning System, Remote Control Alarm, M Sports Package II, Auto-Dim Interior Mirror, Elec Fr Seats + Driver Memory, Headlamp Washer System, Park Distance Control, Front Foglamps, Rain Sensor, Automatic Air Conditioning, Anthracite Headlining.
£21,750



Dealer:

2004 54 Reg BMW 3 SERIES 330Cd M Sport 2dr
2 Doors, Manual, Coupe, Diesel, 27,000 miles, Silver. Full BMW Service History. Free Servicing/Maintenance pack untill 2009. What a stunning looking coupe. You've got the style, economy, power, comfort, reliability and the BMW badge. Full M Sport Kit, Heated Black electric Sports leather with memory seats. Full Conquers pack. ABS, Traction, Climate, Auto Lights. All Usual Dealer Facilities.

£21,495

Would be intrested in hearing what you think...

Thanks

Tim