Hello Rob, and welcome to the forum.

Your problem sounds like a classic bad electrical connection somewhere. I would be tracing all the earth (ground) points for a start.

Check each point on the frame for corrosion, and then pull each electrical plug in turn, and make sure the terminals are clean and tight. Spray them with some contact cleaner. (WD40 will do if you don't have contact cleaner.)
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Andy.
NSR-WORLD.COM

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