Front sun roof leaking could it be the drainage

Generally with the sun roof, If you open it and look in from above, If the drainage is blocked you will see excess water that wont go away. If there is no excess water then the chances of it being a blockage are minimal, its more likely to be a gap in the rubber seal allowing the water to seap through to the interior. If it is the seal, which i guess it is as they crack over time, then these are generally quite cheap from your local motor store.

Hope this is of some help the discovery sunroof is very much like the renault clio and the problems are the same. If you find that the pipes are not blocked then it will be that the water is coming in under the sunroof frame. Any water that gets under the frame will not get to the drain pipes. The only way to stop this is to remove and reseal the sunroof. As a guide you can follow my info on how to fix a clio sunroof they only difference is you need to remove the sunroof visors and storage compartment at the front before the headlining can be pulled down to enable you to get to the bolts also remove the motor from the sunroof.