Could be that G.INP was activated around 05:30 this morning on my line as it reset itself for the first time in months.
Old stats were: Max. down 74615 - actual 73445 - S/N 6.3db
Today's new stats: Max. down 78889 - actual 73997 - S/N 9db
Now all it needs is for the DLM to get it's finger out and tweak the speed up & the target S/N down.
Pity they didn't do a DLM reset automatically so as to speed the improvement up.
Looks like G.INP wasn't activated, but probably a firmware update to the CAB (as reported elsewhere) was.
My improvement lasted a few days before the DLM had a total meltdown.
The max speed went up again by over 10mbps but the actual connection speed dropped like a stone to below 60mbps, with nightly resyncs (between 5 & 6am) just making things worse.
A call to BT resulted in an engineer callout, he tried 2 DLM resets but then gave up, then he did a lift & shift which sorted the problem.
Since the I'm stable, up time is over 9 days, no nightly resyncs and an acceptable speed.
Upstream Downstream
Current Rate (kbps) 20000 77186
Max Rate (kbps) 29553 78363
SNR Margin (dB) 12.2 6.3
Line Atten (dB) 8.5 3.1
Still an improvement on my old connection speeds so worth the effort I suppose.
Let's see what happens later this month, if G.INP does get turned on again, will I get my old 80mbps profile back (after 2+ years)?