Thanks for the info.
I had a look today and sure enough it was the rectifier plug melted by the black Earth lead.
The engine management light was flashing 4 long and 6 short.
I removed the wires from the plug and put them straight on to the rectifier.
Started the bike and the engine management light stop flashing.

I presume it was just the plug melting and the black wire losing contact that caused the problem.
I am hoping the rectifier will be ok and I can hard wire it up and seal the wires.
If not i will go with the fazer mod that's been mentioned here, thanks for that by the way.
I will try and upload pictures of what I did.