Should have said really: I'd rather not be burgled at all, obviously, but if
I was I'd like to make it really difficult for the ****s to steal my pc, or
at least more difficult than just ripping it away from its cables. I thought
about bolting the case to the desk but that would just be a PITA for me when
I buy a new toy for it.

OK, this is probably a crap suggestion, but remove the right hand panel
(hopefully its one that simply slides to remove, and doesn`t require
moving at an angle etc), drill and fix it to the side panel of the unit
at the correct height.

You might want to use the left hand panel, having had a second look at
the unit :-}

To secure it, simply slide the base unit into place onto the now-
attached side panel, and lock in place with (preferably) a thumb screw -
should only need one at the top, which should still be fairly readily
accessible.