I was right:

[root@dipsy /root]# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw 0 0
/proc /proc proc rw 0 0
usbdevfs /proc/bus/usb usbdevfs rw 0 0
/dev/hda6 /boot16 ext2 rw 0 0
none /dev/shm tmpfs rw 0 0
none /dev/pts devpts rw 0 0
automount(pid697) /misc autofs rw 0 0

Success, I can now be fairly sure that if the power goes out for more than 20 minutes while I'm away that I won't be stuck with a Linux box that won't boot. It is protected with a UPS, but only the Win2k box is setup to shutdown cleanly at the moment, the Linux box just gets it's power yanked after 20 minutes on batteries.

Right, time to go and cut the lawn...