12v socket - 2005 VW Trident

Hi
I have newly acquired a 2005 Trident and have found there is no power to the 12v two pin socket.  I have taken the front off the socket and checked wiring connections which are sound but there is no power input through the wires when the leisure battery switch is on.  I have checked fuses which are all OK and all the other 12v applications are working.  I may be missing something obvious here but can anyone offer any ideas.
Ian

You may have fused 12v positive to the socket but a broken earth on the other side. You can easily check with a multimeter.

Hi
Thanks for the suggestion but I've checked the wiring into the socket with a multi meter and it's dead.  The wiring doesn't connect to the 12v switching arrangement and seems to go straight downwards down behind the panelling.  Do you know where it sources from...? i.e. the 12v fuses in the consumer unit or direct from the battery perhaps. ?
Ian