Average wait is 3 months.
I just had a script returned by WR. Hit me quite badly as it was exactly what they wanted, according to their Commissioning PDF.
In it, it said that the BBC are desperate for a female led sitcom for the 16 - 25 age group for BBC Three.
I sent them something that exactly fitted all demographics.
It came back 3 months later, with no notes, but it did have a huge coffee stain.
Go figure.
Writersroom!!!!! READ the BBC Commissioning for God's sake!!!!!!
That's probably what the problem is. All they seem to be trained to look out for are writers for their Continuing Drama team.