Sunroof drain tube location?

Hi guys....this morning I got a surprise when I jumped into my 06 Td4.....There was a small wet patch on the headling adjacent to the middle of the sunroof on its left hand side. It did rain heavily last night and the car was parked across a slop. From the angle that it was parked, I am guessing that the rear pasenger side drain tube is blocked.
In the LR service schedule it says lube the guides and clear the sunroof drain tubes.....which I take to mean that you can access them without dropping the headlining.......Having climbed up there and has a bit of a mooch, I can not see where the drains start, so I can clear them out.....Any help would be much appreciaited.....

Drains are at the front in the sunroof corners and drain away down the A pillars I think.

the tube on the fronts do go down the side pillars .

Two drains at the rear corners as well that go down to the rear wheel arches.

Many thanks.