Righto, had to disconnect mine today to fit a sat-nav hardwire kit. Before I put it back in place I had to turn on the ignition and the headlights came on.
After rebuilding it all, the headlights wouldn't switch off and the foglights etc wouldn't work.
Spoke to the local dealer who told me to bring it in Monday for a T2 check.
Disconnected the battery for 30 mins just in case to no avail.
Out of sheer frustration I reconnected the switch with the ignition live, and lo and behold the switch and all other functions started working.
May save one or two of you some grief.