A6 C6 - Water ingress around wiper linkage and ECU box

Hi All, 

this is a long term issue that I have been reluctant to go to a mechanic for because I am stubborn and like fixing things myself. However, I am now starting to question whether something is an issue or not. 
 

Approximately 1 year after buying the car (2011 A6 C6 3.0 TDI manual) my wipers stopped working completely. I was quoted £500+ to have them fixed, I bought used linkage from a breaker and replaced myself, resealed the windscreen scuttle panel with 3M weather sealer (probably the start of my issues). 
 

2 years later which takes us to October 2024 I discover a huge amount of mush (leaves, soil, water) in and around the linkage area and ECU box on the opposite side of the engine bay. I sucked out and cleaned as best as I could, water seemed to drain normally after that. I cleaned the old 3M weather sealer from the scuttle panel to windscreen joint and applied a more flexible black silicone sealant, which when dry feels like rubber. 

A month ago I clean my car (snow foam, pressure washer etc) and afterwards I lift the bonnet to dry the plastic cover at the top of the engine bay (the plastic cover that slots into the plastic scuttle panel). When doing so I notice a load of snow foam that had found its way into the crevices near the ECU box and the wiper linkage area. Not much water just foam, I use an air duster to displace the foam and dry the area. 

2 weeks ago I discover water in the drivers footwell after rainfall. 
 

Yesterday I remove the wipers, scuttle panel, wiper linkage and realise that when I cleaned out the mush in October, the grommet gasket that allows the bonnet release cable and some electronic wiring passed from the engine bay to the cabin, that grommet isn’t seated properly around the grommet passing into the cabin, which is how the water got into the cabin. I seated it properly and then also put some black silicone sealant around that gasket. (By this point you’re probably thinking about investing in black silicone sealant shares with me around)

Like before, I refit everything and resealed the scuttle panel with…… you guessed it…… black silicone sealant, this time though I put some in the groove, pushed the plastic panel into place and then smoothed over to create a seamless joint for water from the windscreen to pass over and into the scuttle drain. 
 

Had a little look this morning, footwell is dry! But looks like water is still getting into the linkage and ECU area. At this point I’m wondering if that is just normal behaviour and I should just allow it to happen. Looking at the drivers side wiper drain hole in the panel, it seams to just drop the water very close to the grommet that was letting water pass into the cabin. 

i have attached 3 videos. 1 of the mushy leaves and soil, 1 of the foam/leaf discovery and 1 from this morning showing water that is found its way to near the linkage bushings and ECU box. 
 

If anyone has a greater understanding of this matter then I really would like to know, I’m at a crossroads between putting everything into this car to keep it going (it’s only at 92,000 miles) or selling and going for something like a newer (2016-17) A6 or A7, which would possibly have its own set of problems