So after abit of electrical work. And your advise. The reason for the problem. Was the voltage regulator, wasn't regulating correctly. So after a 5mins of running engine. The voltage gets upto 15.5v. Then disconnects-overheats. And electrics fail. So I bought a new regulator. However in the photo inc. The highlighted connections,to the regulator. When separated. We're full of fluid. Which was the cause of the fault. I put the new regulator on after drying connections. And it works perfectly now. (I suspect,the old voltage regulator, still works also) So if your reading this post. With similar issues. Before you buy, a new voltage regulator. Separate the connectors. And check for fluids in the connectors. Hopefully this helps someone. Many thanks Laser Steve