No diagram Mark!
Take a look at Stephans website for the original wiring diagram or look at the top of the dexta page at 'looking for information? Heres how to find it'. The second post by Oscar, third item is my article on Modernising a Dexta's wiring which may help also.
Regards
Jerry
Bath
UK
Jerry Coles
Camerton, Bath, UK
West Highland White Terriers, Dexta's, E27N's and DUKW's