Hi guys, sorry I've been busy and couldn't get into this issue again.
Thanks a lot for all your replies. Really appreciated the help here.
About the questions of being non-UK member or not, yes I'm in the UK. The line is in Waltham Abbey (EN9).
I haven't seen any particular lights flickering or something like that, but I will try to check. I've notice some works overnight from Thames Water, which are going close to the cabinet, but don't know if that might be affecting.
Attached are new QLN and ES for the last few days. Important to say, the line had come down in the number of errors a bit during last two days, and yesterday night I had a new resync from the DLM, and I went back to low SNRM on the US, don't think this would affect but maybe it's worth to mention.