I'm in the middle of a similar issue with my girlfriend's new house. A few weeks before moving, I signed her up for BT I1, we got an activation date of 26th September, the day before we were due to move in, perfect.
Moved in, activation date passed, nothing. Left it a few days as we were too busy to worry about internet. Then went onto the BT live chat, after about 45 minutes the woman I was talking to found out from BTO that there was a 'congestion problem' in the cabinet, and wasn't a lot more helpful than that. So I did some research on the issue and found it's due to the cabinet being filled to capacity. Did the line check and it came up saying it's in a queue.
Several live chats and calls to BT later, it seems BTO have been out to the cabinet last Friday and today, and the online tracking now shows an activation date of tomorrow. So I am assuming they have fitted a new line card to the existing cab. It appears a lot of the footpath has been dug up around it too, so god knows what they are doing.
So I have everything crossed that it finally goes live tomorrow.