Lighting fault trips electric

[Fjpaul]

My bedroom light developed a fault two days ago, tripped when operating switch, fault finding has shown,
1. The lamp has not blown
2.Replacing the switch made no difference.
3.removing the ceiling rose and having just the wires sticking through the ceiling did not cause a trip.
4.refitting the ceiling rose and lamp connector again caused a trip.

My limits of knowledge lead me to think the rose has a fault is this possible?
What should be the next item to try and replace as access above the ceiling is extremely difficult to obtain.

 

[Aragorn84]

how many cables are present at the rose?

 

[Fjpaul]

Sorted
The lamp connecter had failed on the live, slight discolouring of the brass screw led me to it.At least the Mrs will be happy, one job less to worry about.