ok, i got out my measuring stick and have the following.
The turbine entry size makes more sense in inches, it was a round edged rectangle 2" by 1.5" the cormers were roughly 12mm radius.
the stud holes were all 9mm in diameter and were arranged in a rectangle concentric to the turbine entry 73mm by 40mm (centre to centre)this didn't seem to corespond to anything in inches.
i have a picture of a rubbing i made off it with my dirty fingers, PM me your email address and ill send it to you.