Update!
Many thanks to Weizenbonk for the free pair of posts.
I purchased the remaining 3 sets required from Adventures in Homebrewing in the US. Postage was expensive but I picked up a couple other bits and the overall savings paid for the postage.
Postage took 2 days to get from the US to Canberra, then with typical Canberra efficiency it took another 6 days to get them off the local Courier company who were the last link in the chain.
Anyway, I'm glad I did it. The disconnects although $10 a pair are made in Germany and very nice. In comparison to my crotchety ball lock disconnect they are much much easier to to put on the post, first one I couldn't believe how easy it was and had to stare hard at it to make sure it was actually on so easy!
Another thing I discovered worth mentioning is that my spear O-Rings kept getting squeezed out and the edges cut-off. In my research I found that a typical cornelius ball lock post as fitted to my converted ball lock posts is actually a very slightly larger thread, meaning the O-Ring was being squeezed out into the larger bore and cut off by the smaller pin lock male thread.
There are actually special ball lock conversion pin lock posts with the correct bore size for this reason. Std cornelius ball lock have an inside bore too large.
Overall I'm very happy with my swap back to Pin Lock posts. I converted my kegs back for about the same cost as the SS Pin lock disconnects which were my other alternative, solved the spear O-Ring issue, fixed the gas leaks, the posts are much easier to tell apart and the disconnects are vastly easier to use.
After going through this my advice to anyone with pin lock kegs is just to stick with pin locks. If the disconnects are too high you can get German made short posts anyway.
Soooooooo, anyone need some used ball lock posts and disconnects?