I'm done testing for now. The server is shutting down cleanly when the power has gone. Might need to tweak the timings a bit so the battery doesn't run down completely, and can survive a second mains failure in a short time, but I'll get to that later.
You won't get a warning if this happens though, as my router is not supplied from the UPS. Not that this is likely to happen anyway. Those sequoia have a far bigger impact on stability
