Problem solved today - but not by me.
I bought the pinball from Tony @ the pinball shed and he arranged for Ken Shipley (as he is fairly local) to come around as all part of the service - a big thank you to both guys as I would not have discovered the problem.
Problem: the top 6800 processing chip on the MPU board was stuffed and once a few tests were done and chip replaced the game was back in action. Ken showed me a neat little tip for the 8AG fuse (small discontinued one) and that was to de-solder and re-solder the clip upside down so it now can take a 3AG fuse which is readily available. In addition Ken found a few fine cracks in the terminal solders on the back of the solenoid driver board and did a little bit of soldering and all is sweet.
I didn't fix the problem but learnt plenty from it, thanks guys and thank you everyone for your support.
Now to enjoy the game.
