Thanks for all your responses chaps!
After studying the wiring diagrams and comparing them with my wiring, it has become apparent that "Major Bodge" spent many an hour tooling around with the wiring and his soldering iron. [smiley=chairshot.gif].
I've decided to the leave rerouting/extra wiring as it stands and see if repairing/improving the dodgy connections helps.
So far I have replaced 3 connections to the ignition switch,removed a very poorly soldered "nest" of wires close to failure behind the headlight and replaced it with a proper quick connector .
Repaired a busted diode.
Discovered dodgy,corroded earths, unprotected and exposed wires and identified the connectors grouped together in the connector harness.
Hopefully, as I go I will fix the problem. Unfortunately I still haven't found it.
No matter what happens things can only get better.
GREMLINS BEWARE!!! [smiley=shoot.gif]
The moral of the story, if the wiring looks like its been messed with don't wait to find out.