G'day, Rod... yeah, they were quite widely available; I bought mine from a shop in Dunedin called Bristol Piano which was the Mecca for youngsters who fancied themselves! It was the butterscotch/black pickguard model and was horrid to play because of the neck profile; for me, at 17, it was far too fat. Or perceived to be far too fat!
There were other Diplomat guitars on the racks, if memory serves - not always a given! - there was an LP in black and another Tele also in black. I think the older guys avoided them because they weren't Fender, but gee; we weren't exactly spoiled for choice in NZ in 1975!! A cobber of mine had a Holden LP which was very nice, and I'm equally sure it was a re-branded import. I do know as soon as I found a Fender for a reasonable price, I bit the sellers arm off....
Oddly, though, I had a German amp, not a NZ one - Jansen, Holden or Gunn - like everyone else; a Dynacord Imperator with a Jansen duo box and it was just epic!! Sold that in the 80s to fund my Holden Reverb 100 combo which I've used ever since, and now resides with a friend in Toowoomba - I've grown to like little combos because they're light to carry about; that Holden weighs as much as the Moon!!
And yes; Qld is lovely - warm and comfortable! We moved back here from Europe to be warm and it's worked a treat so far!