I sold the M4 though wizzle.co.uk
Similar in some ways to WBAC, but basically it's offering the car to the trade via that portal.
I got a couple of K higher than WBAC, it sold on the first morning of posting, deposit paid that afternoon, car collected the next day, no quibbles.
They even bought a spare set of alloys I had for £2k on top (expensive M wheels)
I sold as I've gone from 25k miles a year to 2.5k (at a push) so have no need for an expensive youthful car for a daily driver, so sold up and replaced with a D2
I would not have sold if I still needed the youthful reliable dependable car, as the prices are all relative and would have had to pay over the odds for its replacement. Having said that, we did swap SWMBO's Mini for an M340d in May, we caught the tide perfectly gettting a really good part ex price for the Mini, but bought a slightly older stock ex-demo that had not yet escalated in price - it was a £40k retail car that I could now get £42k for trade, but not selling. Besides, it's just back from a £1,200 paintwork correction and ceramic coating.
BUT...
All of these services will knock your price down when they see that car if it has not been accurately described.
All these complaints about WBAC (Roberto!) are from people who just plug in their reg number and mileage, ignoring the kerbed alloys, scratches and/or interior issues, then expect to get top whack clean trade price.
The problem is not WBAC!!!