NTL tech support seem to believe it's a problem local to me.
They sent a hit to the box and asked me to reboot. This did not clear it. They're sending an engineer on Sunday (?? - didn't know they had engineers working sundays??)
Strangely, devices plugged into the stb are receiving an IP address of 192.168.100.50 - not a valid internet address and not one of the usual addresses you get if you need to reprovision.
It's just a shame none of my neighbours have an open wifi router
