Thanks for your reply.
I know cable uses (semi-)dynamic IP, however since we joined NTL, a good few years ago, my IP's has only changed about 3 times, and has always stayed in the 213.106.127.* range.
I just thought it a bit strange for them to jump to a completely different range, not that it matters.
As you said, it is most likely to do with some kind of network reconfiguration, possibly since our area has only recently been upgraded to the bandwidth options. (3Mbit in my case)
I would have expected them to put a notification of work on their status page though..
Any thoughts?