First of all you need to check what ADSL Modes (G.DMT v ADSL2 v ADSL2+) you are connecting at. Generally you can lose 3 dB of attn. going from ADSL2+ to ADSL1/2.
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 17 Meg Untweaked 19 Meg Tweaked WBC