I'm not modding, I'm improving
Well put it this way, mine on 69k, 02 reg FASH was 7.7k. I know this is trade in prices, so going to be lower than private sale, but that figure seems low to me. Plenty of dealers/private sales going for 9k+ on PistonHeads etc.
Personally would print off a few examples that you can find, in your condition/age/mileage and use those to get to 8k or more.
For the time and effort, could be worth 500-1000Ł.
edit; I bought mine less than three months ago, to clarify.