There is no switch in the circuit. From what little I've gleaned from research, it seems simplest to put the timer switch in parallel. And to use a single pole (no negative or earth) type of timer switch. But that's where I get out of my depth!
I have 3 outside lights controlled by one pir motion sensor. There is no other switch for them, nor a plug/socket of any kind, the circuit is connected directly to the mains. I want to add a timer to the circuit so they come on and stay on for a couple of hours till midnight, then the pir takes...