Info on very old autohelm

[mug_c]

Looking for info on a very very old autopilot - made in England - which has an line extending from the main unit to
second arm with a string - The main
unit looks like it mounts in the same manner as a modern tiller pilot - but the extra unit has me baffled.

When the string is pulled - it rotates a flange on the bottm of the pole. There is a mounting flange other end - but I can not think of where it would be mounted. The casing on the main unit is red and it only has one switch - for power. I have no manual or any idea on the manufacturer. The unit has an abundance of included hardware. Has anyone encounterd such a beast?

Thanks for any help offered..