Looking across dealers, there are many on 13 plates, with similar miles to yours, are on resale for anything from £8200 to £9500, so its s fair old range, so if you knock off £1500 to £1700 the dealers are looking to make, then £6 to 6.5k trade in at the bottom book is probably somewhere close, though usually on PCP the GFV is set about £1k to £1500 below its actual value, this to cater for "worst case" bikes which come in at 3 years old. I asked this question on the last few bikes I have had, the answer was the same from different dealers. For me, I rarely go beyond 3 years ownership, but that is a personal choice, yours hasn't done a lot of miles, so as you have found, its not an easy choice of what next. In your position, I would go see dealer before its exactly 3 years old (not in winter though!) and ask the question, if you don't like the answer you can walk away and put 2 years extra warranty on it, if you decide to sell later on, the warranty is a good selling point.