Ironically I was standing around at Autopro for about an hour today trying to work it all out :)
Meaning, it was earlier than when you guys replied! But never mind, I looked up Ecklers on my phone and worked out the AC Delco part, then we cross referenced it to the NGK part. So I ordered them in, and they had them later that arvo. Did the change before it got dark, but managed to shatter the ceramic part of 2 of them in the process. As I was putting them in I worked out that the metal part (where the lead attaches) is fatter on the NGK than on the Autolite APP26 that came out of it, meaning it was too stubby for my spark plug socket to fit over nicely without some serious jiggling. I had to go by feel since I couldn't see below the manifold, and both times I assumed the socket was on properly, turned it and "crunch". Have learned a sore lesson, and they'll be getting another 2 plug sales out of me tomorrow...
I hate learning the hard way.
thanks for your replies though guys, this will of course prove useful for future spark plug changers that visit the forums :)