www.honestjohn.co.uk/carbycar/

Afternoon; not exactly the answer you are looking for, but used car price guides that you can obtain in newsagents generally also show the price new. For example, I have on my bookshelf a couple of them. One was from April 1970 ( price 4 shillings ) that, for instance, shows the new price of a Triumph TR5 was £1271 in 1967 and £1350 in 1968. The other guide ( april 1988, cost £1.30 ) shows that a 1988 ferarri Testarossa was £62666, or a Ford Sierrra 1600L was £7760.

Not all show multiple years, but find the right back-issues and you could have a huge database !