Phone think auto, they have a lot more on offer than they list on their site and are pretty reasonable and quick for specials (they have them all programmed in CNC so just run it off)
Right in the end up i have managed to not require an adaptor.
Instead i took the original adaptor, sanded/ filed down the threads on the m12 x 1.5 end and recut the threads to m10 x 1.5.
Seems to still be a good amount of "meat" on the bolt so hopefully no failures at that point.
thanks for the help anyway folks!