Many thanks John07. Your pic suggests there are a further pair of spigots/drains? on right hand side of box.

TBH it's only on rare occasions I've suffered from spits of water coming through vents but your post invites further investigation.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone