ceiling rose connections

I've just replaced the light switch and ceiling rose/pendant holder in what is to be our nursery. Everything seemed okay, I checked the light operated ok after I'd fitted it and there appeared to be no problem. However, later on I went to turn on the bathroom light and it came on but dim, and at the same time the nursery light came on, also dim. I tried the two other bedroom light switches, and both turned on the nursery lights instead of their own room lights! Whilst amusing at first, after a number of hours spent today trying different combinations of wires to terminals I am no further forwards. I have also gone through the potato peelings and old cat food to retrieve the old rose and terminal block, rewired it to that and seem to have achieved the same effect!! Now either I'm doing something very obviously wrong which I can't spot, or I have a poltergeist.

Any suggestions? Unfortunately the wires from the ceiling aren't labelled but I think I have deduced which is the switch cable, and there are the usual three black, three red and three earths into the rose from the ceiling, and blue and brown from the pendant.

I did try wiring the light switch the other way around and it made no difference.

Lastly, when I bought the switch I had the option of a one way or two way switch, I opted for one way...... maybe I should have gone for two way as I'm still unsure of the difference

Thanks in anticipation.

see for refernce it shows how it should be done, you will also need a multi meter, after all you have screw drivers etc don't you?

Look in the reference sticky for info on wiring diagrams.

You need to be able to id the feed in, feed out and switch wires. The reds from the feed in and out plus the red from the switchwire go together, but to nothing else. The two blacks from the feed in and out go to the neutral of the lamp. The remaining core (return from switch) goes to the live of the lamp.

Double check you have got the wires in the switch the right way round.

Sounds like you may have got what is meant to be a live feed to another light connected to the switched side, rather than the common.

ID all cables, check your diagrams and reconnect.

As Breezer says, you need a multimeter to do wiring just like you need a hammer to put up a picture hook.

You've got the wrong blacks connected together. What should be the neutral for all lights further on in the circuit is actually connected to the switched live in your nursery light, so that when you switch on, say, the bathroom it is putting that light on in series with your nursery light.