Ok I think I was too excited when I seen your last example @Deltakosh. It was close but not cigar. However thank you for your help so far - really. Rotations and orientations are still a dark art to me and I am slowly getting there.
So I’ve made up a new version with your code - and the axis is on the ground to show you all the problem.
Once the camera moves - the axis mesh moves with it - however I thought it would of always aligned to the floor. This was my bad as I indicated that this is what I wanted. It is close - but just not there yet.
Second problem is shown on this version https://www.babylonjs-playground.com/#LRGBFS#4
The axis is attached to the camera and once it rotates so far - it jumps back to another angle. The axis in theory should rotate 360 degrees, though I am aware it uses Yaw, Pitch and Roll so different values I believe from reading the documentation.
Thank you all again for your help