Thanks Mike,
As this carrier had very little paint left on it and nothing from which I could discern the pattern, I figured I had some licence to adopt the NT colour scheme.
The grey is is as close as I could find to the AWM sample and has been correctly applied using a brush (with stokes at right angles to the line of the curve) over the green. With a bit of practice, it's surprisingly easy to get the curves and they have this sort of slightly sharp/ slightly feathered edge.