Yes Light 1 works and switches on and off when wire A is disconnected from wiring in Light 2 (obviously Light 2 doesn't work), and lights on the rest of the downstairs lighting circuit all function.
Hallway Light 1 rose I have replaced fitting and is working, so it is Light 2 rose which I can't work out what to do with all four wires.
Yes there are two lights in the hallway Light 1 and Light 2 both have 4 two core wires. Light 1 has been replaced and works and has black and red from two...
Took down two old hallway light 1 and light 2 ceiling roses to replace with two new light fittings. Both lights were working before, both lights are controlled by the same switch system(one downstairs one upstairs). So managed light 1, but got carried away and forgot to mark switch wires live...