Chris G wrote:
Or you could even just create a new virtual machine and tell it to use the existing disk image file(s).
That's the route I went in the end.
Something to be aware of when doing this: MAC addresses will change, and that can break some distros (eg Ubuntu) which will end up with eth0 (no longer there but configured) and eth1 (there but not configured). It's pretty easy to fix once you've worked out what's going on.
The challenge was more because I knew I should be able to recover a deleted-but-still-open file but didn't know how, and couldn't think of a good way to search for it on Google. As it happens I actually found out by searching against the subject I used for this thread with "Linux" added to it. Doh!
Useful to know how to do it for future use, though.