@sevenlayermuddle I re-read Kitz' piece about MSR, the lowest speed achieved during the period. It seems however that my most recent "SNR reset" operation (ie. me hitting the button in A&A's clueless.aa.net.uk server to bring in a new downstream target SNRM) was something other than what I thought it was. The fact that the MSR shows up as a magic number, 2272, is highly suspicious. Firstly, it's magic, secondly it hasn't actually been that low at all, not even close, during the ten days in question. So basically, I don't know what on earth I'm talking about. I'm thinking I've initiated a training phase when possibly I haven't. I would presumably have to get the ISP to do an MSR reset for me and that's all I can say. ISPs presumably don't want to, because an increase in FTR increases their liabilities and therefore their costs.