. . . I would say even a Home Hub 5A (Lantiq) would be preferable to the D-Link . . .
Your mileage may vary with a Lantiq chipset. I know the other line here on FTTC (VDSL, with an attenuation of 9.4 dB) was syncing near full 80/20 on a Broadcom chipset using the Billion 8800NL. However, switching the to the Plusnet Hub One (which is a modified HH5A) caused a lot of disconnections (as the SNR dropped into the minus figures very often), hightened error rates (I do not remember exactly, but it was enough to bring browsing and downloads to a standstill) and even a replacement exhibited the same behaviour. This caused the speeds to drop to under 67 Mbps (I think) and it took a
very long time to recover to roughly the same speed as before.
Previously, on ADSL, I had the TD-W8970 (v1 I believe, which has a Lantiq XWAY VRX268) for a period of time and it was just so damn unstable with the same symptoms as mentioned above. I admit, it was a fairly attentuated line at 42 dB. But the Broadcom-based Technicolor 582n and Billion 8800NL could happily hold sync at around 7700 Kbps downstream at 6db, even with fastpath.
. . . but I'm pretty sure you won't be able to use one on a TalkTalk circuit as it is locked to a BT username and password.
Oops, I should have mentioned that it was locked down for clarity sake. As far as I know, Home Hubs will work on Plusnet and BT connections only.
Do you know, can I flash other firmware to the HH5. It's sitting here doing nothing...
I am not sure about the HH5
B. I know it is possible to flash the HH5
A with OpenWRT, but you would need the Type A variant, confidence in your soldering and understanding of serial.