Hi AlfaPat. Thanks for your suggestions!
The car is a 5 door so rules out the light cluster.
As you mentioned i think it maybe a bad joint behind the wing.
The water is coming in thru the inside of the sill and not thru the door card.
Same symptoms of when the rubber gromit is missing from behind the arch and enters the sill cavity i have checked this and siliconed it to be sure.
What makes this harder to find is i cant replicate the leak with a hose pipe.
It only leaks driving on a wet road.
Is the joint visible behind the wheel arch liner? Or is it a wing off job?
For a moment when I read your reply , I thought I wrote it , a bit of dejavu!
Let me explain I have been trying to trace my wet footwell for 2 mths now, after hosing here there and mostly the bottom right corner of the windscreen , drivers side , I struggled to identify what area exactly was letting the water through. There was always a delay in seeing what was leaking and not was not.
On Saturday I worked out that the water must be entering from behind the top of the wing mount, but couldn't see exactly where. I got the silicone out and as much as I could , sealed up the area around the top wing profile that sat against the A post leading down from the windscreen . I also took the inner wing protection off and tried to more silicone on the A post up under the wing itself, , it's impossible to get at the whole area as the uppermost part of the wing goes too far up to get at. I have still let the water drain out the bonnet hinge area which ends up down the inner wing down the seam where the abs lead is tracked , this seam was also letting water in to the inner sill so that was sealed up also all the way from the top next to the strut housing.
Any way to date the floor has stayed dry , I am clinging to hope here. , but always expect the worst.
I have to say I was nearly scrapping the car as I have a further three 147's outside and none them let water inside!
To top it all , I thought I was still in one the petrol cars and put 10 litres of petrol into the diesel tank before I noticed my mistake ! I immediately topped the tank up with 50 litres of diesel and hoped for the best, it wasn't take me long to decide if the leaking water into the footwell and the engine fails for lack of lube.
Looks like your leak could be the same though?