All is still fine. I'll be trying the Zyxel later today (unfiltered) to see if the errors rise rapidly like before, if they do then I'll switch back to the DrayTek but if they don't then I'll use the Zyxel for a while and upload to MDWS again.
The other day I switched back to the old TalkTalk network for about 30 minutes then moved back to the new network again as requested by AAISP. This fortunately updated the line rate on AAISP's side so I'm now getting the full speed (79.9Mbps, synced at 79995Kbps at the moment). They're currently looking into why my line rate is apparently not updating when I connect via the new TalkTalk network.
I've also developed a script for my Ubiquiti EdgeRouter
(I'm not sure if I should upload it here? Maybe someone might find it useful?) which should automatically update the QoS download and upload bandwidth settings based on what AAISP's tx_adjusted_rate and rx_rate is for my connection at the time (thanks to their CHAOS 2 API). I need to test this but it looks like it should work as intended.
Here's the stats from my DrayTek Vigor 2860Vac (unfiltered) for anyone curious: https://pastebin.com/raw/VJfcgmHtI'm pretty sure FECS is actually just meant to be FEC errors (not FEC seconds). Otherwise I think the stats look fine and assuming my line is on DLM's 'speed' profile then I'm well under the ILQ red threshold for error seconds per day. It will be interesting to see if the Zyxel still gets the excessive errors, if it does then I won't complain about it as I can just use my DrayTek but it will be odd if the Zyxel did still get the excessive errors.
TBB BQM Graph: https://www.thinkbroadband.com/broadband/monitoring/quality/share/3d855252126bb4c241c275ad78d3880f302ee22d.pngI'm still getting under 6ms to YouTube which is superb.
I'll either edit this reply or post a new reply a bit later today/early tomorrow to mention how the Zyxel performed. I'm hoping I can leave that connected and let MDWS monitor my connection again.
EDIT: Forgot to mention that my next door neighbour also said their FTTC connection has improved since the engineer visits, coincidental? Haha.