Could you explain this ceiling light wiring?
It looks a bit of an unusual setup, but I'll hazard a guess that there is either a further light on the circuit either fed from one of the switches or the power from the circuit is fed in at a switch and feeds on from here to another light (or lights).

(Obviously, you need to verify this, as we can't tell how it's wired from just one photograph).

From left to right, you likely have:


Lamp neutral
Circuit neutral (in / out)
Circuit neutral (out / in)
Circuit live
Live to switch
Switched live
Lamp live


The three core and earth cable (red / yellow / blue) probably comes from the switch. There is probably also another three core and earth running between the switches. 

Have a look at the backs of the switches; this might give you more of an idea of where the power feeds to / from.

Usual warning... take care and switch off at the consumer unit before working on the wiring.

If you're unsure at all, you should call in an electrician.