20 years that's some going & must also be some dedication Simon, I've seled the other top areas around the rear of the weather strips right at the back quarter below the roof rails, it p**sed it down today & the area that was getting all the water on the drivers side is dry as a bone, I did however still find maybe 10 to 20ml of water in the wheel well that had drained down from the side to side seal there, the one under the boot catch & inside the well, I'm hoping that it's just residual water from the previous day slowly making it's way out, but I plan to get the hose on it again to check it, but may not have to after looking at the weather report, seems p**sing it down again for a few hours tomorrow, so one way or another I'll find out if there's still a small leak, if there is I am now clutching at straws on where the heck it could be getting in, but I really want to eliminate every single leak no matter how small, fingers crossed but it's not the easiest of areas to check with no exterior seal there or any obvious areas above now where it could be getting in.
if it is still leanking a tiny bit I have a hunch it's inside the tail light where the panels join, but I have looked at them very closely & although they look a bit ropey on the photo, I can't see as much as a 1mm gap anywhere, but will be getting a little tiger seals on them just in case.