did you just put it around where the wiper arm meets the scuttle? Its also worth smearing a bit where the windscreen glass meets the rubber frame 

Have traversed that familiar path before Tigg.

Tunnies suggestion about the wiper spindle holes is well made.  I would also check the grommet in the main part of the scuttle which allows the feed pipe for the driver’s side washer nozzle to pass through.

On my car water was getting past this in into the rain deflector (foam pad) and thence into No 4 plug well - although there were breaches in the welding on the plastic seams on the outer edge of the deflector at several points and around the spindle holes.

The deflector was soaked and I ended up removing the scuttle entirely to get the thing dried out properly as it holds a surprising amount of water.

I was also surprised to find that the rubber trim that locates on the bottom of the windscreen had been dislodged from its seat thereby allowing water to migrate past it onto the back edge of the deflector probably adding to the problem.

I considered replacing the entire scuttle (with deflector) but when I approached the dealer the server allowed himself the merest hint of a smile before telling me that the part was no longer available.

Anyway I dried out the deflector, sealed up what needed to be sealed - paying attention to that grommet – and have been problem free for several weeks now.

I’ll post up some pics of what I found later on.

Windscreen trim moved upwards to show debris behind it (had moved off its seating on the windscreen edge for some reason).



View of bulkhead and scuttle drain well showing water migrating away from the well towards the middle of the scuttle (by way of the rain deflector).




The deflector seams had breached at several points on the outer edges and around the wiper spindle holes (how, is unknown).

I had to change the passenger side dis pack on my Mig, the spark plug wells were full of water and the dispack had multiple cracks and splits, I poured a jug of water over my windscreen to see were it was leaking and it just poured out of the scuttle joint were the sponge is, I had to stop it after fitting the new dis pack, I removed the pollen filter and managed to push the nozzle of a mastic gun almost into the joint of the scuttle and pumped a load of silicone in there, I then squeezed my hand in and pushed it all round the joint with my finger.

Then from inside the engine bay I pumped more silicone round the joint and pushed it in again with my fingers, I left it for awhile and then cut a couple of strips of Denso tape and sealed the joint right up, you can mould the tape round any bumps and you need to push it all round with your fingers so it sticks everywhere, I poured another jug of water over my windscreen and not a drop came through the sponge area or anywhere else except where it was meant to go through the now unblocked scuttle drain 

If you use tape I really reccomend Denso, i dont think flashband would be suitable but you never know  Denso can withstand extremes of temperature and shouldnt dry out, you should be able to pick up a small roll for a few quid from any decent plumbing supplies shop.

Quick Update.....

I've checked all the plug wells this afternoon and all were dry!  However I have no spark on No.1 (Front offside) which is leading me to think that my bargain secondhand dispack might not have been such a good idea after all...  Although before I fitted it, I gave it a good couple of coats of silicon, especially where my old one had corroded and it was fine in the dry....

I'll try a different lead tomorrow, but I fear the worst....

Unusual to get only one not firing due to the "wasted" spark. You say new plugs are fitted, have you checked that #1 plug actually sparks

Yep, No1 plug is good, as was the lead when I swapped 1 & 3 around and there was no spark when I put No3 into No1 at the dispack..... If that makes sense? 

It does seem starnge though, because the dispack looked to be in good condition and was fine for a while after fitting it.   But as soon as it got wet.......

Seems you're right Omegod..... I noticed that there's a 12 month warranty anyway on the pattern parts...... If only I wasn't so tight...