It has nothing to do with the new green cab and fibre!
It is likely that you are not in an AOL LLU area and BT supplies your BB under contract to AOL and BT has upgraded your exchange from 20CN IPStream ADSL Max to 21CN WBC ADSL2+. Either that or AOL has removed the 8 Meg cap on your LLU ADSL2+, but I would not expect that.
Post your router stats and tell what exchange?
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC