Thanks for all your replies and help this is my guesswork so far.
Possibly pistons as the rings fitted in them fine but they were pistons I had used before and never gave me a problem
Possibly the breather which I notice has been spoken about already. The guy who done the engineering work for me also botled the bottom end together and I am wondering if the crankcase breather is blocked. The oil seems to circulate fine but I have had it wet sump once and when I started it unusually it did not cover the garage floor which is suspicious. That to me would indicate a breathing problem, the bike not mine :)
The only other option is a cracked cylinder head (this head I did buy off ebay
) But as I had new valve seats made and fitted I would have expected any crack to become evident during that work or when I heated it up to fit the valve guides. I have not had the primary case off but it did have a new oil seal fitted on that side so I dont expect that to be the problem.
Looks like there is no easy fix then its take the damned thing apart again
The only other thing that occured to me was if the pressure relief valve was not working correctly that maybe crankcase pressure would build up then and force oil past the rings as it has nowhere else it really can go but I would have expected more signs of that and oil leaks galore which I dont have.
Thanks for all your suggestions as soon as I finish a Trident I have on the bench I will strip the damned thing down again