Oily rag

Hi all,

I believe I have a common problem, on my W204 C180.
I have water leaking onto the top of the fusebox, in the engine bay,from around the drivers windscreen wiper post.
The seal is built into the windscreen scuttle panel and therefore not replaceable without replacing the whole scuttle, (pricey!)
The area around the wiper post is damaged and I would love to hear if anyone has an effective diy remedy.
Silicon sealant springs to mind but it but it is difficult to make a decent job of it.
Any suggestions please.

Thank you, in advance,
Oily rag.