insane: looks like it was only DSL services as my VFX service remianed up. I'm using another ISP for my DSL.
It was within their network, however. My DSL line was up and I remained authenticated, I simply couldn't reach anything more than about 2 hops into the wider network - including XNet's DNS so basically the symptom I had was that nothing would resolve and nothing was pingable... aka fully dead.
At which point I gave up and went to bed.