I recently upgraded to the SuperHub 4 and a 350Mbps connection. Since that time I've been consistently experiencing packet loss on my previously stable (for years) line.
I had an engineer visit on Monday who indicated there was too much power on the line and he fitted an attenuator to reduce the power to acceptable levels. This unfortunately hasn 't resolved the packet loss issues I'm experiencing.
I'm struggling to get any useful support via phoning as it typically takes upwards of 1 hour of holding only to be transferred to another department who handle the Super Hub 4 then to be told there are no problems on the network and it must be at my end.
I've seen people post the following to help with diagnosis: (see next replies)