Vauxhall Frontera Nreg electrical fault involving instruments any ideas?

N reg Frontera has only done 53000miles. When used in daylight the instrument panel works ok but when used at night and the lights are switched on the instruments crash and appear to have switched off but the speedo keeps operating. The panel light also goes out. I have removed various fuses and the fault is not there when I removed the left hand *side light* fuse, can anyone help please.