Does anyone know how different/how much better Tri-Iso super 10 would be compared to Thinsulex used in combination with 70 to 90mm PU foam in a warm roof setup with 150mm rafters. Does anyone see a problem with the scenario shown on the Thinsulex web site with the Thinsulex directly trapped between the rafter and the plasterboard without the use of counter battens. This scenario seems to cut about 25mm from the roof depth – not much I know but every little bit helps.

If Tri-Iso 10 is much better and I am missing out by not using it perhaps I should ditch NHBC who wont let me use it. Does anyone know if Premier or Build Zone are more amenable to new materials?

As you say there is a massive amount of info on this subject, particularly on the previous board, but to save you time my understanding is:
Thinsulux when combined with other insulation materials has all the necessary approvals and will be acceptable to Building Control Officers and NHBC.
Tri-iso has no current approval (although still being allowed by some councils) but can be used, like Thinsulex, if combined with other materials. In this case a U-value of only 1.7 can be ascribed to the Tri-iso rather than the 5 or 6 claimed by the manufacturer.
In my opinion using Tri-iso combined with other material would give better insulation than Thinsulux, but if installed as manufacturer recommends would take up more space.