This one's new to me. 
The good news: My provider is Zen, and they're fantastic, easily the best ISP I've ever been with. They're plainly doing everything they can to get this fixed.
The bad news: After weeks of terrible (and completely unpredictable) intermittency on my ADSL service and a BT engineer visit that found nothing, Zen informed me that we're probably looking at a REIN fault that could take months to fix!
MONTHS! My connection can't be relied on for hardly anything at the moment. Just two days ago it took me three attempts to download a few updates to my Arch Linux system. Last night the connection was down so often I gave up using the PC altogether.
If this goes on for months I'm going to go insane. I used to get 16-17 Mbit/s downstream with a rock-solid connection and now I'm lucky to get a connection at all and when I do, it's usually no more than half that speed. This sucks more than anything that has ever sucked before!
So, anyone with experience of REIN faults here? What can I expect - will it really take months to fix? And what's this I'm reading elsewhere on the internet - sometimes it's beyond BT's remit to fix it? How can it be beyond their remit?!

The good news: My provider is Zen, and they're fantastic, easily the best ISP I've ever been with. They're plainly doing everything they can to get this fixed.
The bad news: After weeks of terrible (and completely unpredictable) intermittency on my ADSL service and a BT engineer visit that found nothing, Zen informed me that we're probably looking at a REIN fault that could take months to fix!
MONTHS! My connection can't be relied on for hardly anything at the moment. Just two days ago it took me three attempts to download a few updates to my Arch Linux system. Last night the connection was down so often I gave up using the PC altogether.
If this goes on for months I'm going to go insane. I used to get 16-17 Mbit/s downstream with a rock-solid connection and now I'm lucky to get a connection at all and when I do, it's usually no more than half that speed. This sucks more than anything that has ever sucked before!
So, anyone with experience of REIN faults here? What can I expect - will it really take months to fix? And what's this I'm reading elsewhere on the internet - sometimes it's beyond BT's remit to fix it? How can it be beyond their remit?!