Thanks for the great and very helpful replies so far everyone.
Lostpianoplayer - thanks particularly for your salient points around supervision and flying discipline. Without a "system" around you (I learnt in the RAAF where there are always plenty of blokes to tell you when you're pushing too hard, and I'm sure GA's no different) you are liable IMHO to get yourself into trouble.
Add in the fact that only experience can produce the kind of judgement that you will inevitably need to save your life at some point, and I think that guys like my boss are at higher risk. Accordingly, I think your points about having a pilot / experienced mentor on call are very well made.
Also interested in the diversity of views around starting on FW vs starting on rotary. As well as the fact that I think a Cessna 150 / Skyfox etc would be a much easier ask to start with, I simply looked at the cost delta per hour for instructional time between FW / RW.
Still, as someone said above, guess it depends on how many hours you can save when converting from fixed PPL to rotary.
thanks again guys - any more opinions still gratefully received.
SW