Ok. I shot off another roll of film. This time using the waist level finder only (not the PME). Camera was on a tripod and I photographed points at 8 feet, 30 feet and approx. 250 feet with 3 different lenses. The WLF with magnifier is much better to focus than the PME. As suggested, I made a note of the focus scale on each lens barrel. The results were not bad apart from 1 shot at 30 feet which was clearly focused behind. The lens barrel focus scale said 50+ feet so, although I thought the image was sharpest through the WLF, the lens barrel was at 50 feet. I went back and tried focusing at the same point again many times, and each time the lens barrel said 30 feet. At this point I cant say why that discrepancy occurred but at least I am happy to use the camera again. The other thing I noticed was that when moving the FLE scale on my 50mm lens away from the Inf - 4 metres, the focus scale on the lens barrel means nothing. That is to say, it is only accurate when the FLE is at Inf - 4 metres. Many thanks for all the replies and suggestions on this question. Much appreciated.