Thanks: if you click on one of the pictures you get a thread with the following advice
There are two pages of nice line drawings of Sommerfeld Mat Type ; Irving Grid Type; PSP Type; and Bar and Rod Type tracking. in Michael J.F.Bowyer's Action Stations Vol 1 Military airfields of East Anglia.
http://publications.drdo.gov.in/gsdl...ca.dir/doc.pdf
The book doesn't state how or where the Irving Grid type was used. This was an American design and not commonly used. I've not seen any reference to it for runways.in the RAF. If you don't have the book contact me offline, but I've also found the following