Ceiling light switch problem

This is a variation on a common theme. I\\\'m replacing a bathroom ceiling light with a new one which has a flush plate fitting.

Firstly I made the beginners error of disconnecting the 9 wires ( loop-in ) with out noting which went to the switch. I therefore had to borrow a meter and by checking the resistance and switching off and on the light found out which flex was the switch. One other thing I found was that another flex also gave a reading which I couldn\\\'t understand.

Anyway I wired up according to the diagrams ie 3 live to connecter with no out. 3 earths to connector then out to earth on light. Black ( neutral but not ) from switch to connector then live out to light. Other 2 black to connector then out to neutral to light.

This worked fine. Light goes on with pull cord switching light on and off.

About an hour after installation I went to turn the light on and there was a brief flash then it went out. I assumed the bulb had blown. The weird thing is that when I went to switch the landing light on ( next nearest light ) the bathroom light turned on. I could then turn the bathroom light off from the bathroom and both switches operated their respective lights as normal. That is I was unable to replicate the problem.

Sorry if this is long winded. Any pointers gratefully accepted.

Sounds to me like it's co-incidence - that is, the landing light switch didn't switch on the bathroom light, it happened to come back on at that moment. Especially if both switches now operate correctly. The bathroom light coming on briefly and then off again is probably due to a loose connection. Take everything apart and check each connection carefully.