My FTTC connection has synced at around 68Mbps for a long time, and around 18Mbps upload (3dB profile on a Huawei cab). A couple of nights ago the firmware on my Smart Hub 2 was upgraded to v0.24.04.11017-BT, and the sync rates are hugely improved:
I've gone from getting a pretty consistent 61Mbps down and 17Mbps up on Speedtest.net to 70Mbps down and 19Mbps up. I'm not aware of any changes being made locally that might have improved the condition of this line - I guess it's possible that someone who was causing crosstalk ceased their service recently and that just coincided with the reboot and resync that came with the firmware update, but my understanding of crosstalk was that it was a cumulative thing.
Unfortunately I can only give you information that the SH2 reports, which is limited.