I've got double skin ones on mine but I can't find them on the market anymore, places like Europarts and Camberly and even the independent suppliers are only selling single skin. Two stores showed on their computers as coming up as double skin but are actually single skin.

Looking along the edge of my old ones you can see the seam with the edges are rolled up in opposite direction-splayed. The new one is rolled downwards at the edges and is thinner than the old one as well

Are they now obsolete and changed the manufacturing process? If I have to settle for single skin one,will it do the job?