Well, there appears to have been a power cut overnight (10-15 mins)

When I looked this time yesterday, there were about 12,000 error packets on d/s (only 100 or so upstream)
that had accumulated over 10 days. Most of those appeared as the the sync speed rose over 10 Mb/s I think.

This morning, 6 hours after the power reset, 0 errors on u/s, 8 on d/s.

Max Rate d/s 17.9, d/s 14.5 SNR 5.8 dB

U/S unchanged since the beginning at 1.2 ish 6dB

At least the reset, didn't take the connection all the way back to 4 megs d/s, !

In reply to a post by broadbandjockey:

When I looked this time yesterday, there were about 12,000 error packets on d/s (only 100 or so upstream)
that had accumulated over 10 days.

Cumulative over the period of the router uptime, not line uptime I think. Don't know about TP-Link, so I am not sure.

In reply to a post by broadbandjockey:

At least the reset, didn't take the connection all the way back to 4 megs d/s, !

Shouldn't happen after a power cut.