I have made a start on the stone walling which encloses the garden and orchard.
The base is 2 thicknesses of card one of which fits into a slot in the foundations of the scenery.
The stones along the top are made from strips of mounting board chopped into small pieces and stuck into PVA. The whole lot is then covered with filler mixed with a small amount of PVA. This helps it stick to the card and also harden enough to be scribed. When dry the stone courses are scribed into the plaster with a sharp metal scriber.
The stones are now painted with watercolour. I used charcoal grey, Chinese White, raw sienna and raw umber in varying amounts to get the colours.
Windsor and Newton no longer seem to do a charcoal grey but neutral tint is the nearest match.