Left side brake light connection missing. PLEASE HELP!

[birdy2712]

So the misses bought a 2008 Megane last year from a dealer in Manchester and I noticed recently that the left side brake light was not working when I followed her home. I have taken the casing a part only to find that the bulb was not connected and the connector is nowhere to be seen! I check the right side (working fine) and there are 7 wires going to the rear lights (2 that connect to the brake light and 5 going to the others). The left hand side only has 5 wires going to it so the brake bulb has never worked however it passed and MOT with the dealer. The car has a centre brake light as well. Can anyone confirm why this may have happened?