Bathroom lights not working despite replacements

[Rachel78]

Hi All,
Yesterday on operation of the pull cord switch for the bathroom lights, something went *pop* and all the upstairs lights went off. Reset the breaker, try the switch again and.. nothing.
Neither the extractor fan - on it's own pull cord - or the bathroom lights will work; the other upstairs lights do.
I've replaced the two switches, 3 of the 4 downlights (the 4th one is ok) and the fuse. I've not touched the fan.
Any bright ideas for anything else a non-qualified person can try aside from calling a professional?

 

[EFLImpudence]

You have a loose or broken wire - where the pop was.

 

[securespark]

How do you know the 4th one is OK if you don't have power to check it works?

 

[dannyboi2003]

Have a look in the loft as there could be a hidden FCU up there running the lights/fan in the bathroom, maybe even an RCD FCU if any work was carried out recently-ish?