Hi Barry, its definitely a Building Materials issue. I spend a lot of time checking everything and it all came down to a select few Building Materials which seemed to be bugged somehow. I rebuilt the Materials from scratch and they work fine now. Its possible that they were Building Materials from someone else's template file that I imported , possibly from a different region version (US). I suspect this might have been the problem.
In the past I have built my project template files off of other peoples template files as a starting point. I think this can cause a lot of issues and I wont be doing it again.