Alfetta heater tap - advice needed

[AlfaACT]

Can anyone advise if
a) this cam looks like an original?
and/or
b) if it has the correct profile?

The cam pivots around hole "P" and is hinged on the small bolt "H" at the top end (as pictured) of the tap housing.

The lobe that operates the tap is immediately below the pivot hole and only operates through a small arc.

The reasons for asking:
The heater has always been either On or Off - no in between;
the cam is a very sloppy fit in the housing;
the arm "catches" on the housing when it is "off";