One of the main reasons for taking the engine out was to find and sort the source of the oil leak / leaks. Am pretty sure that the main source was the main bearing to sump cork seal strips. They were as hard as rock with oil oozing around the joint edges and no flexibility compared to the new cork seals which were nearly twice the size. I throughly cleaned the groove with meths smeared the surfaces with hylomar and squeezed the new cork seals into the joints. Soon after refixing the sump – with new gasket – over the cork seals to hold them in position. Am pretty confident that was the source of the oil leaks – time will tell.