How to dismantle the wiper motor

[crazy horse]

hi guys,
i have seen how to remove and fit a 12v conversion for my wipers and am in the process of taking it apart to clean it up too.
kinda got stuck when i got to the removal of the shaft that the linkage fits on to.
i have taken off all of the screws and the ally housing on the back of the motor but i cant get the linkage off the shaft and dont want to break anything so could do with any idea of how it should be removed,its a bit rusty and i have managed to get the nut undone that fits below the linkage but it wont budge.
please help as i need to get the plate that it fits to painted aswell.
many thanks

[lightice]

Mine was held on by a circlip.

Difficult to see as it was crusted in grease. But after cleaning up I could undo it easily.

All linkage parts were secured with circlips on mine - 66 bus.