I’ve used Ebay the last 2 times I’ve sold a car (Mark IV Golf about 4 years back and then, a a couple of weeks ago, our poorly Skoda Octavia Scout).
Both times I’ve started the bidding at the absolute minimum I’d want to accept and set a Buy it Now for a little above the book price from Parkers. In both cases the cars have gone for over the BIN price – the last one was without a working engine so was advertised for spares or repair and I still got a very decent price for it (only about £500 less than I would have got on a main dealer trade-in with it in full working order).
One thing I would recommend if you go down that route (apart from being COMPLETELY honest in the listing) is state in the listing that you are not interested in offers and don’t stick your mobile number in the listing (you’ll get plagued with stupid offers by text) – ask people to contact you via Ebay and don’t be tempted to accept offers outside the site – you’ll almost certainly get a better price from letting it run and are covered by their standard protection terms.
Webuyanycar is useful if you want a quick hassle-free sale but you will lose £££s – my experience is they’ll offer you less than trade in a lot of cases – cheekily if you don’t commit straight away you get a follow up email a week later telling you your car has miraculously increased in value!
If you don’t have a Parkers book or login then you get get a reasonably accurate and free valuation here: http://www.motoring.co.uk/