Right been out to garage and got my spare convertor , the manifold ( male ) end is 3/8th npt , ie 18 threads per inch with a major diameter of just over 17 mm , the female end is M12 X 1.5 mm , I am trying to source some of these cos they seem to be one thing that is as rare as hens teeth , might just have to make some though .
Hope this helps .