Click/tick sound A pillar 05 KZN165R

[Cobbo]

Was hoping someone has had found and fixed a random click/tick coming for bottom of A pillar, corner of windscreen on drivers side. It is driving me crazy as I can't find its source.
I have tried everything. I have confirmed that it is not the dash as I have had it stripped down. Dash removed, right mud guard off, A pillar trim off, door open or closed, bonnet opened or closed and it is still there. It can be heard outside as well sounding like it is coming from the rain box in front of windscreen. I have rolled down a hill with the engine off at below walking speed walking beside it and it an be heard inside and out. I removed the cover over rainbox and checked it and there is nothing inside that could account for the sound. I am now thinking the sound may be transferring to that area from somewhere else, but where? I even had guy that works for GMH finding rattles in new cars put about 10 hrs into finding it with no result.
So far with all I have done nothing has even changed the sound, the BUGGER is laughing at me and it's driving me mad. Any help would be greatly appreciated, thanks