Sold another car on AT last weekend, ad' was on one day and the first to see bought it. I use the safe number system and don't publish an email. Correct valuation and simple fact filled ad's work every time for me.
IMO Value to sell = price of an equivalent age/mileage car within reasonable travelling distance (for that type or value of car), then minus £10. This gets you to the top of the search results, you are the first to be called and as long as the car is correctly described you have a sale at or very close to asking price since you are already the cheapest. Never failed me yet.