And the difference is?
Printing a kitemark is only marginally more complicated than printing "CE" in sans serif letters. So I don't see how it helps... Even if you give each product a unique identifier, a knockoff can have the correct identifier and still be a knockoff.
But industry mouthpiece indeed. We'd prefer to fit some modern insulation -- cheaper, faster to install, thinner, and better insulating than the kitemarked standard. We can't as the BCO won't accept non-kitemarked kit, and it's indeed Foreign Made [the horror!] so it won't get the mark. Kitemark it and another UK company would go bankrupt, but really why would you want to support an obsolete products?