Hi Jamie,
Had a similar experience with a Zafira B diesel six months ago.
Car cut out for no apparent reason & would not crank over.
By the time it was recovered to mine it did start under its own steam.
20 odd DTC's, This also had Engine control unit programming fault & CAN bus malfunction codes along with a shed load of low power codes across the ECU ranges.
This was a taxi with 90K & original battery, battery test was inconclusive so it was changed anyway.
He has had no problems since, but by the same token he had not had any issues before that time.

Just my twopennorth, as this is spookily similar.

Cheers, Tony.