Thank you to Jay for the prompt. A while a go I posted about some door mats I had picked up from Lidl and thought they would make ideal ploughed fields.
Here are a few pictures of them cut up. No other work done.the base on the fields are about 2mm and the ridges 3-4mm.
The figures are blacktree and mounted on 2mm bases. The fields work well with 20mm and I don’t see a reason why they would not work with 15mm. I have placed against a doormat corn field. As you can see it hides the nasty rubber base easily.
I managed to get 5 fields per mat and at 99p a mat, a bargain. They are thin, but this makes them flexible and the backing means they do not move once placed. They may benefit from some dry brushing but that will have to be another day.
They are currently back in the shop but I have not seen the price.