Leaking concrete tile roof

[skwmk2012]

I have just just been crawling through my ceiling chasing a leak in my 27 year old concrete tiled roof.

What I find is that there are no broken tiles but that there are drops forming on lots of the tile clips as shown below ...

My guess is that over time, dirt has accumulated above the tile clips under the overlapping tiles and is creating little dams that collect little bits of water which trickle down the clips.

In most cases, the drops seem to just run down the tile clip and into the hardwood battens and dissipate to dry off when the weather suits such but a handful drop water below.

In most cases this is a non-event because I have aluminium batts on the ceiling joists on which the droplets collect but not in such quantity that they pool and run off but in one or two cases, they have done damage to the Gyprock ceiling.

To solve my immediate problem, I have bent one tile clip a little so that the offending water droplet seeps down into the roof batten.

What is the longer term solution to stop water dribbling down the tile clips, please?

Is it that the roof needs to be water blasted from above to dislodge accumulated muck under the tile overlaps?

All advice gratefully received.

Roof Painting l Gutter Replacement