Lighting electrics- what's going on here?

[Puggit]

Another leftover from the house we've moved in to. I've removed the fitting from theach ceiling that contained 4x 28W bulbs and found this...



There are 3 main cables coming in, each with live and neutral. The live cables are on the left. 2 enter the block on one side and one is connected to the other side.

For the neutral cables, 2 go in to the bigger block together. The 3rd neutral cable goes in to the right of the block, with a brown sleeve!?

Inside the unit we have this:



As you'd expect really. One connector is neutral and one is live - feeding off to the 4 bulbs.

I'm confused by the wiring coming out of the ceiling!

[Puggit]

Every other wiring I've ever changed just had 3 wires: blue, brown and green/yellow - hence my question.