The 52 and 56 plates are very different, but the MK1 is still a very capable car, and you sound like the kinda person who is actually going to take care of and respect the car, not just thrash the crap out of it and generally be a bit of a ****** with it!
The MK1 is a very good car for what it is, and if you do get one and enjoy it, whats to stop you trading it in for an MK2 in whatever, 9 months, 2 years, whatever you feel!
Another reason to go for the cheaper car is that in 1.6 guise it may very well seem just what you need and nice enough, but you might find yourself yearning for more power and realise you just spent 6k on a car that although you like, you're left wanting more power from it as the 1.6 might not be enough for you after a while! (Take it from me, I know but bought a 9k 2004 Civic as my 2nd car a year after buying a 1.3 Fiesta, great car, but if I'd known what I know now, I would have grabbed a Type-R or a modestly priced Focus/Something of that nature)
The Golf MK2, doesn't really seem to fit in with what you want here, so ignore that

I'd say go look at a few used ones in local dealers, go to look, not buy, see what 3.5k will get you, should be a nice 53/04 if you're lucky, but its the history, rather than the age that matters.