Apart from the grill on the top plenum chamber / windscreen panels it’s strange why one side of the windscreen panel is closed against debris entering the chamber and the other side left open?
If debris gets into the chamber it can block the drains causing water to fill the chamber damaging the pollen filter and electrical circuits.
I bought the foam which is a breathable cell foam that doesn’t absorb water generally used to filter aquariums.
A bit of measuring and cutting to shape the foam to fit and then a bit of trimming to a shape that filled the gap nicely. Easily cut with a pair of scissors.
Had to buy a piece 60x60x5cm!! ….. so think I’ve got enough of the foam left to make another dozen of them!!
Guess if i were doing it again I could have bought a smaller sheet say 1″ thick instead of 2″ – but am sure this will come in handy for other things.