
I've been with TT 3 years and changed my original contract to TT+ getting a Huawei HG532 router which at the time gave me a speed test result of 11.7Mbps.
You could never have got 12 Meg throughput on
that line!
Something doesn't add up! Have you retried the Huawei, as another suggested, to confirm the Down attenuation?
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