Hi Geoff,
I often experience outages and from checks I've run they primarily appear to be DNS related. I haven't had any success with the tortuga address on the two times I've tried, so when I get in its via orbit.
I've emailed my ISP's helpdesk and asked them to cast an eye from their end and see if they can spot anything I haven't. They haven't responded but I may have to chase them up. If I learn anything that might be useful I'll pass it onto you.
Regards
Alex