Thank you for all the replies to my query. Be assured Epiphany, that I won't be doing the calcs in the cabin as collective and cyclic are applied. More like ensuring my own safety in case it all goes wrong.
I couldn't get the link to the AP to work (as usual) but found a hard copy extract. delta 3, yes I have considered carefully all the forces with the help of the AP but I still found the maths helpful in that it factored in the horizontal component of rotor thrust, for a given scenario. If you want to amplify on the maths, please do.
Contributory factors (other than roll momentum) I've come across:
Angle of slope with the ground.
Total mass of the ac.
Distance of ac C of G from the pivot point.
Amount of tail rotor force which adds to the rolling force (if tail rotor is facing the 'wrong' direction into slope).
Offset flapping hinges with disc level, producing a centrifugal loading which tends to roll the ac up slope.