Ok here are the pictures you requested. Is there anything I can try to eliminate the PIR 1804, control box 1812 or the 1819 switch so I can try and pin down which is at fault? as I said, been working for months with no problems so can't be the settings, must be an intermittent fault as after a reset i.e. turning the power off and back on it starts to work as normal for a day or two the reverts back to not working again.