Neck pup volume drops randomly

Hi all,

I've got an issue with the neck pup on my 2008 Les Paul Custom.....

For some reason, the volume on the neck pup keeps dropping in and out - if I toggle the selector switch fast, it comes back on. It had happened previously, so I completley re-wired and replaced all electrical parts of the guitar (pots, switches, caps etc.). However, it's starting to happen again!

The bridge one seems fine, it's just the neck.

Anyone have any ideas on what it could be and how I can fix the chuffin' thing....??

Thanks!