T3 Rewiring. Help needed...

I’m part way through a full rewire for a T3 and am using the 1978 Haynes manual as the guide. I’m working on the Lighting Circuit and am confused by Item 42 which is shown as being within the headlamp shell. The legend says that it is a “Light Switch, with stop device from position High-Low Beam to position Parking light.” Can anyone translate that for me and suggest what is actually needed? Any help is much appreciated.

Item 42 is the parking light bulb, the description is wrong and refers to switch item 13. This diagram is for an early 850 T3 with the older style switches. I can supply you with a coloured wiring diagram that is a lot easier to read, see here http://diltondesign.co.uk/phpBB3/viewtopic.php?f=64&t=16390&sid=50bb03d93704b1fce493734609a5b2a4

Ian, I have sent you a PM. Best regards Chris