Just spoke to Plusnet they have put it through as a fault and will get back to me, I assume this is why I'm having such problems, it isn't normal for the SNR to drop from 6.5/ to 5.4 is it?
If Openreach look into this and they see the low SNR and errors on the line, what's the chance of them fixing it? Would they see this as a fault, even though clearly it is.