window seal

Noticed the other night that the window behind the drivers seat is leaking slightly so need to get it sorted before we set off to France this weekend. The window looks like an aftermarket slider and the water is coming in above the slider inside so I'm guessing either the rubber seal has had it...

I hope I am positing this in the right area. when I was taking apart the front driver’s door to fix my central locking, I noticed that the front internal window seal had perished and was falling apart. I was wondering if anyone knew what the part name / Number was or where the best place i...