'Progress' report:
Last night went to the gym and attempted dumbell bench press. Warmed up rotator cuff thoroughly and worked up from light weights but problem was still intensely there. Worked back down to very light DBs (8kg) and tried all sorts of form changes from powerlifting style 'scapulae back and down' to bodybuilder style bench but no change at all.
Did releases on the area with tennis ball and lots of stretching last night..little improvement today. Same again tonight. Tried also some 'rubbing a soccer ball against the wall' with sh. abducted 90 degrees, elbow bent both facing wall and away...this temporarily reduced the noise in my shoulders during abduction. Tonight lay prone with thoracic extension, flexed shoulders in scap plain to activate lower/middle traps...got good activation and will see if this does anything.