I am getting ingress of water into the cab from what I believe is the sunroof area. I have told that the problem, which is apparently a common one is that the drain pipes from around the sun roof become brittle and crack allowing water into the headlining which then drips down.

The dealer has quoted £300 to replace them. Given that I never use the sunroof and it is a work vehicle does anyone know if it is possible to seal the drainage holes, maybe with silicon.

Any advice would be appreciated.

You can seal them up if you don't want them,quite often its where the sunroof is sealed to the roof panel which causes the problem as it did on mine.Ideally its a headlining out job to do it properly.

Did mine 2 years ago,no problems since.Put a thin bead of sealer round the outside of the sunroof frame between plastic and roof, I tried everything else ,this was my last resort and it solved the problem, I wouldnot block drain holes if they are doing what they supposed to ,hope this is some use.

If your not too precious about appearances from above, what I do is run duck tape over the gaps between the glass and the rubber seal of the sun roof over the winter, then come the Summer (well, the nice two weeks in late August, or if I take the Disco to France!) I peel it off for a short stint!

You don't need drains if your seals are ok, the drains are only at the front so no good if your facing up a slope.
Justdo a search search loads of threads on sunroofs and don't use the bath type of sealer it won't last.

Search feature is your friend
I have/had the same problem, water leaking onto the headlining which when you move comes shooting out of either the passenger or driver side seat belt pillar (much to my surprise one morning! - was ruddy cold!) After that little incident I went all out to try to nip the problem in the butt.. (Just done the repair last Saturday). - Take the below as a guide, May not be 100% correct but this is how I managed it..

First off - to do a proper job is carefully (take your time), remove all the trims, - grab handles, sun visors, etc, (The trickiest trim for me was the passenger and driver side door pillars, there is a push clip (Just add a bit of leverage to pop out) at the top but I found I had to remove the door seals to get at four metal clips which grab onto the door frame under the seal), the trims around the windscreen pillars pop out as well, I found a plastic trim removal tool was invaluable, only a few quid off fleabay.. After a load of faffing about, the headlining can be dropped (it is possible to do the repair work with the headlining in place but its a right pain!! - it will go out the back but its tight and needs a lot of careful squeezing/angling then you can remove the pipes (I used a small gas-powered soldering iron - blow lamp attachment) to gently heat the drainage pipes so they were softer thus easier to remove.

Drop the drainage tray where by you can remove all the old sealer off the plastic drainage channels, clean up and re-glue (I used Araldite- good stuff! - I never heard of the stuff until three weeks ago when I started to look into a fix for the leaking sunroof issue)

Once the drainage trays are removed, the sunroof will push up - I used some plastic trim removal tools as a bit of gentle leverage and gently pushed the sunroof up, breaking the old silicon. - clean up both the roof and the sunroof tray - Ideal time to replace the seal in the actual sunroof it just pulls out, clean up, tad bit of silicon and pop the new one back in - careful not to stretch the rubber like I did :doh: end up with a tad extra and have to start again.. (I'm learning!-slowly)

Add silicon (I used "Tiger seal" as that is what my local automotive store advised) to the rim of the sunroof assembly, put back in place and reattached the drip tray tightening the screws evenly - I put a bit of silicon on the washer part of the screws (but that's my choice, as I have seen water drip from one of the screws).

Touch wood! - so far so good, been absolutely hammering it down the past few days and no water in the cabin!

If I can do it, anyone can! - All thanks to the wonderful people on this forum who took their time to help me!

Heres a link to my forum topic on my issue: http://www.landyzone.co.uk/lz/f8/sunroof-motor-187493-2.html

And a few more related to sunroof issues:
http://www.landyzone.co.uk/lz/f8/sealing-up-sunroofs-186363.html
How to Repair Your Sunroof - The Causes