Annoying knock from camshaft front pulley area

[Austin in the Shed]

It is much easier to remove the gear with the cam out,best in a press,leg type pullers can damage the rather fragile cast iron teeth in my experience.
Mag engine owners more so as the force required to break taper can result in the center breaking out of the gear.
Austin material quality and machining was top class and providing the engine has been fed with reasonable quality oil the camshaft and followers will run a high mileage.