You do not automatically loose the vat on a new car, I've heard this loads of times and it simply is not true. I bought my new Golf R for £28600 and sold it to a trader 8 months later for £28500. I've bought a few other cars and sold after a year for around 10-12% loss. Supply and demand dictates car prices, vat doesn't come into it, loads of salesmen go on about the loss of vat, but it's just their way of justifying their profit margin.
OP, put your car on Tootle and try Sellcar, you'll get more than the likes of WBAC, just remember January generally isn't the best time to sell. To get top money you need to sell privately, but selling cars privately above £20k is tough and most buyers want them for less than trade price in my experience, total time wasters. Nearly all of mine have gone to traders, I never part-ex, I usually stick them on Autotrader and state on the ad that I'll consider sensible trade bids, nine times out of ten that what I get and that's where I end up selling them.