I haven't tried any of the fixes suggested there yet. I did however updated to
3.17.3 and the box survived yesteday without crashing. Is there anything in
3.17.3 that could have fixed or at least partially mitigagted the problem?
Should I stick with 3.17.2 until you have save more definitive clue as to what
is causing this?

It usually takes a few hours for the crash to happen so I might just have been
lucky though. I'll keep an eye on this report my findings in the "BUG 85647"
thread.

Thanks...