Went to pop in release bearing to pressure plate, heard the retainer ring pop off and fall inside the pressure plate.... tools down and walk away.
Fast forward a few weeks, drop 6 speed out alone, remove and fit new Exedy bearing cage and retainer ring and reinstall gearbox.
Photo shows the original ring on the left and Exedy on the right, difference being the diameter which would affect stiffness.
102720705_257260048866316_3296020440696848864_n by Aaandy Livingstone, on Flickr