What am i misundertanding here Mark? I was under the impression that u-value calculations in the UK must be derived according to thermal conductivities measured via Hot plate testing. BR443 sets this out doesnt it?
This implies [to me] that since Part L is the UK mechanism for European Compliance [with the EPBD] that the conductivities measured via the subordinant BR443 referred to in Part L are compliant.
Like I said, I may be missing something here, which, is really the point of my original qusetion, ie better understanding.