So I decided to have a go at this today.
First I removed the wiper (17mm nut), the trim under the wiper (pulls off with gentle force), trim at the base of the windscreen (also pulls off) there are also a few circular clips to remove holding these bits of trim together in the engine bay.
Then I began to remove the roof/windscreen trim starting from the bottom of the windscreen.
The first clip is different to the rest and is easily broken, to get it off without breaking it you need to push the edge of trim nearest the screen down towards the windscreen glass and lift the back of it at the same time. It should come away without breaking. It's a sort of plastic fly clip. (I managed to break half of it later)
The rest of the fixings are different all the way up the side of the windscreen. There are 4 to remove. I had to get creative.
I took a thin screwdriver and bent it with pliers to give me an angle to get under the trim.
These fixings don't just pull off with force, they need to be released. There is a male part which is attached to the underside of the rubber trim that inserts into a female part that's attached to the car.
I lifted the trim at each fixing, as much as I could without breaking them, just enough to expose the side of the clips that need to be released.
Then I used the bent screwdriver to gently push in the wee push clips that are holding the male part into the female fixing and managed to release the clip, there's about three of these wee catches or clips on each fixing that once pushed enable you to pull it off.
I worked my way to the top of the windscreen, there were 4 of these fixings in total.
As far as continuing to pull up the trim on the roof goes these clips are different and they just pull up with force, enabling me to inspect under here as well.
Once removed I also removed the female parts up the side of the windscreen by lifting the catch with a screwdriver and sliding them across.
Then they just come off.
Then I was able to inspect the underneath and assess the state of it (it was a bit of a mess). There was dirt, gunge and old crumbly black sealant.
I also pulled the rubber tim across the top of the windscreen to about half way across.
I could see that all the way up the side of the windscreen and across the top of the winscreen there was a lot of dirty gunge and crumbling black sealer. I decided to brush away anything loose and then gave the whole thing a good clean.
Now with it all clean I could see a few issues. A small crack on the seal at the top of the windscreen right at the corner, some holes in the body sealer at the bottom corner of the scree and just a general look of leakyness, I knew I needed to seal up the cracks, holes and all around the windscreen.
So I chose some fairly heavy duty sealant/adhesive that I bought in homebase for £10. Seems like it'll be fairly good stuff.
It was! Very thick and sticky. Came out of the tube quite slowly. I used a fake 'finger' silicone spreader and an old cedit card to smooth all the sealant under the edges of the glass and all across the seam of the roof and the side of the car.
Then I let it sit in the sunshine for a couple of hours to set. (I went and cut the grass).
Once dry I reassembled in reverse.
Tomorrow I hose it and see if it has worked!!!
Fingers crossed.