The line tester is not very accurate, and most times a fault in or near the house, is in the street cabinet or on the pole.
This is the charging guide.
You must live in an area with a poor Openreach external network, there are plenty of areas like that
So .....4/01/2014 An engineer calls and fixes problem which is between two telegraph poles somewhere up the street.
As predicted and indicated by socket test ...not in house. Why didnt they investigate that earlier given the patently inadequate results from the so called line test? The line cannot be OK and not OK at the same time yet their tests indicated just that.
Open Reach engineer says not to wait for device to recalibrate stable broadband speed but to ring BT instead. BT man says he cannot do that but only after having me rebooting modems routers etc. Why didn't he listen when I asked him if it was possible? Another case of blind script following.
So.. another wait ..72 hrs .. for the device to establish a stable connecting speed.