Getting to the dash stage, got a carbon one from MK. But do i need to support it with some ally etc, and it will need a 15mm rad on bottom.

I supported mine with a bracket from the back.
As far as the radius goes, no, you can simply use a compressable "U" section trim. See my photos, not too clear I'm afraid but may help.

did it pass ok with that trim?

where did you get it??