The next stage is to service the changer mechanism.
Gently move the lever that controls the arm out away from the cam
Remove the circlip and lift out the cam, you may have to rotate and lift it but it will come out. There is a washer underneath the circlip, do not lose it.
Remove the nut arrowed.
Remove the circlip and lift out the arm this arm is known as 5242 in the service manual