Just-Insulation (http://www.just-insulation.com/multifoil.html) had this to say about the Superfoil range:
“SuperFOIL– for and against:
SuperFOIL manufactures the largest variety of multi-foil products.
SuperFOIL SF19 (40mm) costs less per square metre than any of the other multi-foils that we sell.
SuperFOIL SF40 (65mm) represents the best value multi-foil when comparing cost against thermal performance, ie R Value 3.54.
SuperFOIL SF60 (100mm) is the most robust multi-foil product currently. available, and with an R Value of 4.643, it is, by far, the most effective multi-foil product available today.
SuperFOIL SFUF (6mm) multi-foil for under-floor insulation and heating systems costs almost half the price of its only competitor Actis Triso Sols
SuperFOIL products has LABC Registered System Approval No. RD199-0512. And SF19 and SF40 have BBA Test reports.”