Dyson CR01 Contra not Contra'ing?

Hi all, I have come home to find my Dyson CR01 not contra-rotating (but is running in single drum). I have taken the back off and found that the clutch motor, and clutch ring all serviceable. If i put the clutch assy into single drum it all spins very easy, into contra and the torque level increases, but is still turnable using 2 hands. The machine is showing no fault codes. So i am thinking it could either be 1 of the 2 motors U/S or possibly a control board? Any advice? How can I fault find? Thanks