Suz,
An electrician is safest but...
This site shows diagrams for you...
http://www.flameport.com/electric/lighting_circuits/lighting_ceiling_rose_other_colours.cs4
A Ceiling rose will typically have three cables (each with Live Neutral & Earth) One cable will be power in - one cable will be power out to the next rose and the third will be power to and from the switch. Some ceiling roses just have two cables with nothing running off to the next rose because there isn't a next rose...
So ignoring Earth you will have either 6 wires or just 4 depending if the rose you're looking at is the last in the chain or not.
You seem to have Five wires? It may be that a black wire is "lost" up in the ceiling (the switched live coming back from the light switch) OR possibly and unusually a single Red conductor has been routed from the switch and that the switch is picking up its live feed from somewhere other than the ceiling rose. Take off the switch plate and have a look at the wires in there.
The normal arrangement is to have 4 connections at the ceiling rose...
Permanent live - In / Out / Off to the switch (never to the light)
Neutral In / Out (and to the lamp)
Switched Live - Typically on a wire that looks like neutral but with a red sleeve on it - connects to the lamp to turn it on and off.
Earth
Good luck... Take care...
Peccavi
September 2009