Yeah. they are the PVC kits I'm talking about. I heard the name Foamex in relation to one of those kits somewhere. They are around £30 more expensive than MDF. Yes I think they are around 10mm but not 100% sure. I guess the material just costs more than wood, or perhaps because you don't have to paint it (if you want it white). Just wondered if anyone had used it and how good it is.