Yeah, we thought we'd leave it to you, Dave.
Apart from that, surely any further investigation is unlikely to add anything to what has already been mentioned in this thread. The findings of the internal investigation are probably correct, I should imagine. That is, it's pretty clear what happened ... and how it should be avoided in the future!
Clue:- left to fend for themselves, batteries, by their very nature, have limited capacity! But (as I gave already hinted), ambulance vehicles have an energised electrical system ready on tap!
