I phoned Tech Support last night after another episode of the modem re-booting and the chap did a test on my line and said the power level was well below the recommendation.
He said it wasn't a modem problem.
He was going to raise a job for the engineers to come out and look at it but he did a quick check and found that a call was made at 9am yesterday from someone in SN3 area with the same problem.
He advised to leave it overnight and if nothing cured by lunch time today, I should call back.
At the mo everything seems fine but the receive light has flashed about twice but no re-boots.....keeping fingers crossed its fixed!
Just checked the NTL service status and nothing mentioned and the chap last night was amazed that NTL hadn't put this problem on the page!
Still no upgrade tho MikeyB in same postcode area!
PS Spoke too soon, modem just done another re-boot by itself!
