Water mystery in footwell

[Goran]

I discovered a few weeks ago that my drivers side carpet is wet, not from above but from underneath.
I checked the orange drains either side of the centre console first. They were in good condition, dry and not blocked.
With dread I started searching for Botang's hole. However as the car is LHD I either don't have it, or if I do its on the passanger side so not relevant.

So I started with an experiment. I removed the carpet and loosened some of the sound deadening but couldn't see behind it properly as its huge and the top of it is pined to the bdy work somewhere up high behind the dash. I poured water down the windscreen then jumped into the footwell with a torch to see if any water came in. And sure enough it did but not where I expected, It dripped down from somewhere above to the left near the corner of the dasboard. The only possible entry points I could see from the Engine bay are a big rubber grommet with some wiring loom going into the cabin, a small orange rubber plug next to it, and the pedal box itself. If the butyl cord seal had failed that would be a real pain to re-seal the whole edge of the pedal box. Audi design of the hole in the firewall for the pedal box is not good, there is a flange around the hole allowing water to collect and sit above the bottom edge of the pedal box and body seal. I suspected this was the most likely entry point.
I got some black silicone sealant from Halfords (only 40g - doh!) and proceeded to seal the two grommets and the edge of the pedal box from the outside as best as I could. Cleaning and sealing the two grommets was easy, reaching in and sealing the edge of the pedal box, especially the bottom edge, was almost impossible. I did it somehow in the end with the help of a short length of silicone tubing, although I cant claim the seal is good because I could not reach the edge to clean it first. The best I could hope to do was fill in the channel created by the flange so at least there could be no standing water it would have to slide off.