It was late, cold, I was tired and hungary and i got line to neutral resistnce test failure, literally 0, a short circuit. It was in a lighting circuit. The R1 R2 continuity was ok. I think on reflection, at home at this moment, that it could be that i have switched a loop instead of the switch conductors at the ceiling rose. Anything else I should look for please, a neutral to line fault does not suggest a clip or screw.
Thank you, in anticipation
Thank you, in anticipation