Its out , had the remove head and drilled the bugger out and then unwound the steel left in the thread

It was seized it the point end of the plug .
Where is beat place to get Gasket set for cylinder head as I take it u also need to replace all the push rod tube seals as well ?
The piston cylinder had a metal gasket on top , looked on one site and shows a rubber gasket sandwiched between piston cylinder and metal gasket ?