[buglawton]

Your symptoms sound identical to what I had a year ago. NTL were able so see from the Stats that our link had been down for say, 20% of the time. I pushed to get an engiineer out. He did some measurements involving the signal from the street box and showed us how to see the key figures on a certain ip address page, pointing out how the signal level had been wrong & was correct after adjustment. Since that time the connenction has always been up apart from occasional known wider outages.

If an engineer does come out, ensure he checks the signal level reaching your home (ask if they did that last time). I suspect things go out of kilter as more local people get connected.

Cheers - Nigel