Smell Behind Dash

[dnrc]

Hi Guys, hoping someone can help

A few weeks ago I parked the car under a tree and ended up with a huge pile of bird muck on the windscreen.

I made a big mistake it turns out and used the washers and wipers to try to remove it which at the time stunk up the car. I have since washed it all off and all was ok.

But this morning I used the washers again and it re-activated the smell.

I have taken the scuttle panel etc apart and cant see anything obvious. There

I can smell it along the panel behind the wipers and im guessing its gone down the vent in this picture?

https://ibb.co/gSq5Ytc


Anyone got any good ideas?

I will wash what i can see but dont think i can just hit it all with a jet wash especially the vent

How easy is it getting to that inside the car?

Anyway, any ideas would be appreciated

[dnrc]

I washed everything but after more checking i think its actually my screen wash that stinks

so ignore the above!