Thanks John, it started with car being fine, then, as I was driving I had the Hybrid system warnings, ABS and stability control warnings, battery degredation warning. After a little research I decided to take the power pack out and check for a duff cell (I bought a spare to have ready). Once apart I measured each cell, very little variation around 8.1V each. Terminals had some corrosion so I cleaned them all (have all been checked 4 times now). I put it all back and .. No key sensor, the mechanical lock works the central door locks. Headlights work, horn works. No ignition, no dashboard, no diagnostic circuit. So I took the power battery out again which is now in my garage. The 12V battery is good (12.8V steady). I am puzzled by the Big Black 3rd cable from the bottom of the power pack, Is that a Ground return? Thank for any guidance, David