i cant the i took the old one down without taking note like a plonker
mrdetox,
Welcome to the forum, the post by ProDave above, whilst a little blunt and to the point, does sum up the crux of your matter.
It is difficult if not impossible to explain how to identify the wiring to your light safely on an internet forum, if you get it wrong you could end up killing yourself!
That may sound harsh, and I'm sorry if it does, but, electricity can kill.
Now to try to be as helpful as we can.
You are saying that there are 4 wires, a red, a yellow, a blue, a black, and a green/yellow, and none are contained in the same sheath (outer covering) to give a single cable.
Can you see any cable outers at all, say grey or white surrounding the wiring you have described?
Is this a house, a flat, is the light fitted directly to the ceiling, or is there a box or something else the old light is fitted to on the ceiling?
Please don't touch the wires unless the electricity is isolated.