So I'm still here in London.
/dev/random turns out to be in a patch (112438-03) for Solaris 8 which I've now installed. Now I'm just waiting for the first two disks to sync... and someone's just come in and told me that the machine room shuts at 7pm. Not tonight it won't. I at least want / and /usr mirrored before I reboot (to get the kernel module loaded so OpenSSH can start).
More importantly, my car is going to be stuck at the Park and Ride all night. (I'm not going to get home until about 10pm or later at this rate). I hope no pillock breaks into it.