I was at Smiths, working in the design labs, CH3, and can recall seeing our barbers pole type Para-Visual Director which was invented by Mr Majendie, I think he was one of our test pilots.
Photo as Fig 1 in here:
http://ntrs.nasa.gov/archive/nasa/ca...1969005146.pdf
Correction - Mr Majendie was a de Havilland Test Pilot, which would figure because we were doing the DH Trident Autoland. Saw him once when he visited Test Equipment lab.