Thanks for all the input, that helped a lot. After "consulting" with Simon, I went back to the car and mechanically adjusted the free play between the lever and the slave cylinder by temporarily inserting a socket over the thread of the HEIM joint. Indeed then the clutch did fully disengage after depressing. So it is clear that the fix is to increase the space between the plunger of the SC and the lever to take away the free play. I am going to make the heim joint adjustable to do that job.
I still remain baffled why it did work before the MC swap but lets say that is water under the bridge. Once again, I appreciate everybody's input and thoughts.
Dus Simon , dat werkte inderdaad!
J.