Dirk GentlyDeathy ..... I'd like to see the air vents, or the mesh as it may be called, replaced with something solid that can help keep the noise in.
Is that more important than having a decent pitch to play on? Because the airflow through those spaces is vital for the pitch - not so much grass growth but keeping it free of diseases.
Airflow is just as important as light for a healthy pitch.
Perhaps the club could investigate some sort of roller shutters so that the gap at the back could be closed during matches. No idea if it would help the atmosphere but it would certainly keep the cold wind and rain off the backs of those at the top of the stands.