This is what Plusnet sent me "" Having tested your line today it appears the throughput and speed issues of the connection may be due to a setting being incorrect.
The signal to noise ratio (SNR) is too low for the length of your line. The SNR helps the line to remain stable and unaffected by noise or interference on the line. The higher the setting for SNR, the higher the level of noise can be tolerated.
The SNR for your line was set too low for the amount of interference we'd expect to see, so by increasing this we expect the connection to now stabilize and for the information to be received without interference.
Please monitor the connection over the next couple of days, if this has not resolved the issue, we will then need to inspect your line in closer detail.
Please do not hesitate to get back in touch online via Online Chat or by phone on 0800 432 0200 if we can be of further assistance. "" but i just had a No Net warning