Hi Hoser,
Did not check seals but pressure tested the crankcase it held pressure no problem.
I have a feeling having thought about this a lot that the
Engine had probably been rebuilt at sometime before using bits a pieces from all over. The piston had those wierd marks but the bore was perfect. the base of the cylinder i.e mating surface had one dent in it where someone had obviously levered it off at some time but the corresponding surface on the crankcase was perfect.
I have learned a lot about this beast over the past 2 months so at least I now have a base level to work from.
Thanks again for all of the advice and pointers
Have attached a pic for your records of Pilots you have helped sort.