Thanks for the replies and link guys, sorry I haven't got back to you before now, I've been away with work.
I really appreciate the links and even kind offers to check out guitars on my behalf, however, I'm specificaly looking for guitars from that era (it's narrow, I know).
The thing is, I've been very in the past to have owned a DV-52, a '65 and '78 D-50 and a '78 D-55 and I also currently own a '71 D-50. All were and are great guitars, but none have hit the spot for me like my '73 D-55.
All of the D-50s I have played, though apparently made of the same woods, were coarser sounding (the '65 was very loud). The '78 D-55 was nice, and had class, but the neck was too chunky for me - and somehow it was quite dark sounding. But there's something about my '73 that is quite special: sophisticated, sweet, compressed.
All that said, it might have nothing to do with the year - I might just have a good one. The top and neck have both been sanded down and that certainly helps the sound and playability respectively (my F-212 also has a sanded top and it is the best 12 I have played).
Thanks again, and please do let me know if you hear of a D-55 from that era
Wombat