As far as I know the power is fixed now as the street light is working normally again, I have switched out the modem already on basic diagnostics, the noise is I think external somewhere, but I suspect not far from me.
I have accepted it for what it is now and just await until I move to a FTTP area or get FTTP here, the street light was reported for been a nuisance at night as it kept flashing, and was just hopeful it might have been the source of noise.