Hi,
A warm welcome to the forums.
I think it would be useful to explain how this stuff works in simple terms. A line has a TARGET SNRM for which the router and exchange will negotiate a synch speed to achieve that target when making a new connection. The 'normal' target is 6dB, but it can be set at anything from 3dB upwards in 3dB steps. If a line has a history of instability, then the TARGET SNRM will be higher than 6dB (9, 12, 15 etc.).
After establishing synch the SNRM will vary as electrical noise comes and goes. During the evening continental AM radio interference can cause the SNRM to fall by as much as -2dB. Faulty (or going faulty) electrical equipment can also give rise to depressing SNRM leading to disconnection.
Poor quality internal phone extension wiring can act as an aerial picking up electrical interference and thereby degrades ADSL operation. Interference can arise from switched mode power supplies not working within specification, central heating controls, plasma TVs, white goods, CFLs.... indeed nearly anything. The only way of locating them is to undertake detailed monitoring (see the router stats links below) and / or going around turning things off (unplug them, putting them into standby does not help).
PlusNet can only raise your SNRM to improve stability, but that will be at the expense of synch speed - it is far better to rectify the extension wiring (use good quality twisted pair cable connect only terminals 2&5), look for a source of interference and eliminate it.
Happy hunting!
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
