Anyone here know much about these?
My dad has been having problems his broadband for a while. BT chap says all’s fine up to the house but most days it doesn’t work at all and most others it’s intermittent at best (BT ADSL and home hub). I’m trying to help but really not an expert, I have managed to get it working of a fashion.
Just done a couple of speed tests. Both showed download speeds around 0.67 MB/s, while the upload speeds were 12.8 and 15.9Mb/s, which looks like a bit odd to my eyes.
Any suggestions would be more than welcome.

Unscrew the plate on thebottom half of your master socket and plug the filter in there. That will cut out all the extensions and dodgy wiring in the house. If its not fine when plugged into that, then I'd say its a line fault.

Do you have the filters in correct order?
Has you dad exceeded his download limit?
Had this with plusnet when limit exceeded the speed is then reduced automatically.