I had a crawl under today to check:
The wiring is OK, not broken, cut or stretched.
The DV is a 'G' revision. Is this the latest type?
There appears to be no splits/stickiness in the DV.
The fault hasn't come back either...so I wonder if a long period of sitting has left something a little sticky, and it's freed off as soon as it's got properly hot and seen some proper boost.
All very odd.