Thanks, oh well. Kinda fortunate 3G is pretty good here now, rigged up the mobile broadband instead.
If it helps with diagnosing it, when I dial from landline to my mobile, I get a ringing sound, and at the same time it goes to the answer machine.
Meanwhile, on the mobile it gives my correct number ..... then tells me I have a missed call from another number
Oddly, it's a dialling code for an area a bit south of me, which is going to be a different cabinet I think.