A circle of Slaters Plastikard 7mm Granite Sett embossed plastic was cut using a compass cutter. It is slightly oversized, next time I will try an make it slightly smaller.
There is just enough thickness in the right heel to drill a hole of 1.2mm diameter so the figure can be pinned to the base with some 1.2mm brass rod.
The plan is to add some debris after finishing the painting.