Ok, back in Brisbane and I finally decided to give the manfrotto focus rail a try. I also took some pics as I promised.
I attachedd the quick release plate to the bottom of the rail and the camera directly to the rail (which required a screwdriver to secure properly, which would be a little onerous). The focus rail worked exactly as it should, forward and backward in a pretty smooth motion.
The real problem though is that a tripod and focus rail for field macro work is about a useful as a chocolate teapot
I cannot imagine using it to get any results at all. I have done pretty well without a tripod up 'till now and think I will continue without. The focus rail may come in handy though if I decide to do some studio-type of setup with static subjects.
For macro work outside, imaging living creatures I'd say forget it!