Update : Panic over, modem resynced because of a power cut, now back to normal 8128 Mbps down 32 dB att. Modem must have got upset when BT were fiddling with the wires. Didn't want to do a resync myself because speed could have gone even lower.
Long term PlusNet user on a small rural 20CN exchange, been OK for years running at max 8128Mbps sync (No ADSL2+ available). BDUK project is active here. a lot of rather remote places such as a farm and a couple of houses down a lane have now got FTTP available.
In my village an All in one FTTC cabinet has been installed, a couple of days ago noticed poor internet connection, had a walk to the cab, BT guy was jointing cables to connect up the cabinet so I told him my broadband had gone very slow, he said it will be OK when he had finished but it isn't.
Previous stats 8128Mbps sync 32 dB att SNRM around 7 dB minimal CRC errors
Current stats 2368Mbps sync 41 dB att SNRM 5.1 dB a lot of CRC errors (over 350000 in 24 hours)
It seems that BT have added an extra 0.5 Km of line to my connection, and for the reported attenuation the sync is lower than expected with very high error rates, perhaps its an extra loop of line with a split pair thrown in for good measure!
I don't think first line support will be much help with this problem, I can imagine the conversation, your speed estimate is 2 - 3Mbps and you are within that, but I know that the speed estimate is wrong and always has been. I have almost always had 8128Mbps sync.
I know there are a lot of problems at PlusNet at the moment so don't expect a speedy response from a forum rep but an indication of my historic line stats would be very helpful.