[heero_yuy]

Unbelievable: The first set of fairy lights, about 25 screw-in bulbs made of two older sets, for the hall worked first time. That normally never happens.

40 bulb set will be more difficult as it didn't work last Xmas. I have a voltage tracing tool that looks like a screwdriver but has a battery and LED inside that indicates mains. I'll trace down the wires 'til the voltage goes missing. Then replace the bulb(s).