For that sort of vintage you would be looking at £5500 for a bit of an unloved dog up to £8-9000 for a lovely example with all the stamps.
I paid £7200 for mine 2 years ago and that was a steal...
Around £6500-7000 will get you a good example with lots of toys....make sure they all work.
D2 won't be worth a huge amount, £1500 or around that on a Part-ex...more on a private sale.