Wiring issues with new light fitting?

Hi all, I've just put a new light fitting up to replace the old single light with shade. New one is a B&Q thing with 4 spots.

Problem is, the old rose was knackered & i stupidly didnt make a diagram when i took it down.

Now i've wired it up, and the switch isnt doing anything, so i've made a mistake somewhere.

I have, from the main power...

3 black wires
3 green wires
3 red wires

On the light fitting a 4 block connector, with...

empty
black
green
red

I understand i need it to be switched, so one of the black wires goes to the empty, but what goes to the other side of the empty to create the loop?

Thanks,

Mark.