Tried it both the new maxdnrate tweak and the coddinggain tweak with neither really making any difference. The problem is both the Vigor's lack of stability against short intermittent noise spikes, and it's stubborn insistence on re-syncing everytime the SNR improves.
The DG834Gv3 suffers from neither of these problems (in addition to consistently syncing a few hundred Kbps faster too), and I can happily see a good couple of hundred hours of uptime, whereas the Draytek was only ever lucky to manage 8-10 hours. Shame really as I liked the Draytek which is why I am keeping it at the moment in the hope that Draytek resolve its current issues with Max on anything other than a ideal line conditions.
ZeN 8000 Pro