Aye Up Andibs (and others with self inflate mats!)
I often use a surplus self inflating mat and after frequent punctures (due to the nature of my deployments) I decided to sort the problem and upgraded the mat by way of sewing a piece of recovered material (from another punctured mat!) onto the bottom of the good mat creating a pocket into which I could insert one of the ex BW fold-able ground insulation mats. There is a slight amount of surplus material where the top and bottom halves of the mat are pinched and sealed together onto which I machined the extra material (you have to take care as you do this!) Not only has this solved the prob but I get the extra insulation and damp-rising resistance.
Might be a way for you to avoid further punctures.
PS I also added webbing loops to anchor the mat when there is ground slope.