Thank you very much. There were more problems with the camera than I thought! This was OM-Doktor in the Hamburg by the way. He has done an excellent job.
It may be interesting to know what the camera was doing when in use with those faults. The mirror was locking up when a picture was taken. I wrongly assumed it was an electrical issue when in fact it was a mechanical issue. I actually suspected more than one fault because the frame counter would sometimes reset mid-roll and the battery test would say the batteries were nearly flat when they were not (and then 5 minutes later say they were fine).