Ugh. I’ve had to deal with the country’s incumbent telco quite a bit of late and it can get quite depressing. The support usually boils down to “I’ve done a line test and its come back fine. Can you check your equipment and try again please.” or “Does it have a filter on it?”. BT support has been spectacularly incompetent recently but this time it looks like our dodgy kit is to blame so I have an apology to make to BT and a weird sync/packet loss problem on a router to resolve.