Right it makes sense now, i think.
Took all of it out and pete and matt you were right it has been helicoiled before.
Matt the adapter is the same thread size but its pulled out the helicoil, or in this case snapped it out. i measured all the threads and they are all the same 1.00.
This is whats left of it, the heads all clear
the rest of the helicoil
The helicoil is on real tight on the adapter so for now i have just put it back in till i get a helicoil kit.
Does anyone know much on sizing of the helicoil themselves?