I find it really unusual that with only 2 resets/drop in connection in 4 months that you are in a banded profile as banding normally result of far more resets in shorter timescale
Unfortunately DLM can get stuck and not release banding once line regains stability.
I find it strange that in the first post " line is connected at 67000Kbps" and "attainable rate of 69474904Kbps" from the Draytek suddenly becomes "67000Kbps" with "87329448 attainable" once the Dratek is "hooked up to check settings".
Deos this mean the OP keeps switching equipment?
I am checking the stats by plugging directly into the modem via a laptop, I did reset the modem however.