it was the G30 that was missing :
the new code :
; Uncomment the following lines to lift Z after probing G91 ; relative positioning G1 Z5 F100 ; lift Z relative to current position G90 ; absolute positioning G1 X80 Y50 F6000 ; put head over the centre of the bed, or wherever you want to probe G30 ; lower head, stop when probe triggered and set Z to trigger height