Taken alot of messing around to get a stable line
Any messing about would have been with your home wiring, which will be equally applicable for ADSL2+, from which you should get 12 Meg Down & 1 Meg Up Syncs. Maybe another 1 to 1.5 Meg Down if line is still stable at 3 dB Target NM, which they try to lower it to if at all possible.
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