drainage

I was hoping that somebody with an R231 could check something for me please... As per the photo, do you have a piece of foam in one of your roof seals? I'm in the process of trying to identify the source of water ingress in my 2013 R231 SL350, and came across one drainage channel thanks to the...

I have only had my CL for a month, and have been thinking on and off about checking this fabled drain hole for blockages as I don't fancy £££ worth of ECU destruction and a wet footwell thrown in. I have searched on here but haven't found the info, so I thought I'd ask about where this drainage...