My BeBox has synced at 9.2Mb and 1.2Mb up with a 45dB attenuation and 6dB noise margin.
Send a ticket into BE and ask them to switch you onto Fastpath and a 6dB profile - make sure you mention that you understand that your line may become unstable and reverted back to interleaved etc - touchwood though it'll be rock solid stable with lower latency and a higher connection speed![]()
I thought Fastpath/interleaved wasn't applicable on adsl2+