Actually, this is one of the larger ones.
In still no ADSL news, I have borrowed yet another modem from a chap at work. It seems to be able to achieve brief bursts of connection through to the ISP on startup, which is more than the last one could, but we're not getting any internet connectivity through it. The helpdesk at my ISP is baffled, and, worryingly, beginning to recognise my phone number, but most of their staff (who I am, worryingly, beginning to recognise by voice) seem willing to be helpful and get to the bottom of this mess. We're doing a 12-hr line test overnight, which will give us something concrete to complain to Telecom about.
I strongly suspect that we will find that there is a physical connection in the exchange which is almost but not quite broken. This would be consistent with the dogs-breakfast that Telecom made of our connection when they replaced our exchange back in November of last year.