I have had a problem with mine for 3 weeks.
I also am in NN10 (Higham) and have had no upload and not much download for the last 3 weeks. The reason they gave for this was indeeds noise on the line so you may now be experiancing the same probs as me.
Alot of the time my modem has only the power light and the ready light on with no signals at all coming or going from it.
NTL said that I am on UBR 5 which is NOT the one being affected with the problems of noise but work being done to solve that problem could be causing my problems. Not sure if you know which UBR you are on??
Anyway I hope they are sorting it and my probs are over and yours are NOT about to begin......