Just double-checked on BBC London website as I used to rely on things like this when I lived in Japan. The schedule for tonight now shows "Full commentary from the Championship match between Charlton Athletic and Cardiff City". So I emailed Radio London and got the following response straight back (thank you to them for immediate response):
You will be listen to live commentary of Dagenham v Brentford on BBC London 94.9 and on DAB. Unfortunately, the commentary will not be available online.
This is from the horse's mouth, so as to speak, so I wouldn't rely on BBC London internet coverage.