So, with two layers of card in place I decided to try out some building layouts.
The trees are made in bottle-brush style. The trunks are soft iron wire from the garden centre and the foliage is teased out strands of green parcel string.
In the picture below I've chamfered the edges of the mat using a Stanley knife. In a couple of places the bottom layer of card hasn't stuck to the surface of the mat. I've since introduced some more PVA and weighted down the card with a bottle of whisky and a cast iron casserole dish. Middle class wargaming at its best!
The numbers are to show the position of the buildings.