Brother Eacott....please to remember there is no helicopter flying outside the UK and no authority but the CAA. Oh, sorry....Europe and EASA unless Brexit changes all that....but you get my drift I assume.
The more pedantic of the UK Crowd presume to lecture the rest of the World as though they have the One True Word when it comes to flying Helicopters all the while failing to realize some problems for their diatribe.
(Bold Print added so the non-Pedantic in the UK understand the target of my comments)
With no hill higher than 4,000 feet and max temps never much above Jumper level and underslung work a rare thing and fire fighting all but non-existent....they tell us all about that kind of work. They have a very limited Helicopter EMS industry, do scant hell-logging, no Christmas Tree lifting, and no Banner carrying.
But....by God...they will sure tell you how you are doing it wrong!
I have heard it said..."Teach a Brit to do something today....and tomorrow he will tell you how to do it!".
When it comes to this leaving a running helicopter thing....that adage sure rings true.