You will always get the tyre kickers and time wasters when selling privately. In terms of selling to the dealer - they want to make some money on it so will only be offering 80-85% of what they can achieve on the forecourt: £16k sold to the garage means a bottom sticker price of £19k - I think they're being a bit greedy - no way your car would be up for £19k, £20.5k is more like it.
Sell to a dealer and I think you could expect £17k, sell privately and you're talking £19k - you need to be significantlycheaper than the dealership otherwise the potential buyer will just buy from the dealership.
To put it in perspective, I was offered £18500 p/x for my Sept 63 plate GTD, 5 doors, manual, no extras and Tornado Red, for an expected delivery of my R of March (
). Your GTI might be Nov registered, but to most, a 63 plate is a 63 plate. At best, the fact your car is 3 months younger than a Sept plate is equalled out by your slightly higher than average mileage (My p/x to yours comparison: £18500=£18500). Your GTI has a slightly lower residual than the GTD (£18500>£18000), and a 5 door car is worth £600 more than a 3 door Golf (£18000>£17400). Add in the fact that we're 2 months past March and your car is depreciating £250 a month right now and we're at about £17k trade-in/sale to dealer.
White is by far the most common colour (TR is probably a not so close second, followed by DBP), but most people buying a Golf want 5 doors. Leather/cloth is neither here nor there - no-one expects leather on a Golf, it adds about £300 to your p/x value.
If you can handle the hassle, i'd sell privately and pocket the difference. Tell all potential customers that they need to arrange insurance to get a test drive (that should weed out the time-wasting 17 year old thrill seekers),and to justify your price, have a few examples of current used stock at VW dealerships to demonstrate the private sale savings to be had.
