Advice on what this car is worth

[Crb]

Hi guys, just a little help needed on this one if you can. My fathers just put a deposit down on a new Toyota land cruiser and is looking to sell his 07 Mercedes e280 estate. The dealer has only offered him £7k for it so he was thinking about selling it privately but we're not sure how much to advertise it for. Had a look on autotrader etc but they're pretty few and far between especially as this has only done 33k miles. I think it's going to go against him that it's a 3.5ltr petrol but it's got all the toys and is in very good condition. Any ideas what to advertise it for ?

[Lexx]

I think auto trader are offering free valuations at the moment (based on Parkers most likely).