2cvs leak. Drill some holes in the floor and take the rubber mats out. You're going to drive yourself mad! If you've done the vent flap and wiper spindles its probably seeping through some rot round the screen.

Maybe the only answer is a full restoration... but I don't know if that works (having never had an "as new or restored example) or how long you'll be leak free.

my cars not rusty apart from the toe board, thats the only rusty bit what so ever,

so a full resto isnt neccasary

my windscreen doesnt leak, it used to, and i used to be able to see where it leaked, but i sealed it windscreen sealer and not a drop has come in through since, so that should stop rot round there,

i havent done the vent flap again yet, (dunno if i worded it wrong) im going to re do it today, along with wiper spindles, before i did it last time car used to leak like a siv, got in the car once and there was lake inside!

now its only occsional small puddle, but when i first greased vent flap there was nothing coming in, nothing
so im going to re do it anyway and see what happens

I must have confused your doing the screen with doing the flap... sorry.

ive done both, but the vent needs doing again

I usually end up taking all the insulation off the dashboard and removing the rubber floor mats. That way at least you can see any water that does get in and it's not trapped next to the floor or the bulkhead. It makes for a pretty uncivilized car, but that's how I like them anyway. It's a 2CV, you're never going to stop it leaking altogether.

im not exspecting it to not leak what so ever, just if i can stop water from sitting in places id rather it didnt, like in that back panel, would be a bonus. im going to take the lights out on sunday evening so on monday itll all be dried out (may even do it tonight actually and let it dry over weekend) and then seal the lights up where its leaking in..

It would most likely look like this if you removed the outer skin. Citroëns sealing is holding the water trapped between the panels. Don't think that you can do much except replace the rear panel one day.

is there no way i can seal it up to prolong that?

where does the water get in? and surely if i drilled some drain holes somewhere to let it out?

if it gets in via the lights, if i sealed lights up surely thatll stop it?

so all in all its probably not a bad thing that the water is pissing out there anyway!?

Have checked the bonnet hinge?

Get some duck tape and put a couple of layers right across the sealant where the hinge is welded to the body.

See if that cures the problem in the short term. If it does then get it permenently sorted!

im pretty sure its coming from there, as it doesnt look great, and it comes through on the flat (level) bit, above the vent flap, ill take a pic later, and show you, it also seems to run down the nearside a post inside, but not from windscreen, no idea where!