You are right in the fact that you get less when you part exchange, but this is because the garage has to make a profit and add a warranty to that vehicle. However you need to look at the £1,800 against what private sales are achieving in your area, as you will never get forecourt price for a private sale.

I have to admin £1,190 seems a tad high for a variance. Have you valued your car at all yourself? - http://www.whatcar.com/newautotrader/valuations_search.asp is a good vauation which will show you what it is worth (allowing for mileage) for forecourt prices, private sale and part ex values.

 Worth checking!!

 Regards