He told me (I think) the 'delayed' ordnance was incorrectly fused and went off about 20' below the Jag,
That's the one... he also had a huge problem after coming back to terra firma. There was a strong wond blowing and he was dragged a long way before he could get out of his harness.
There was also another incident later with a Jag's cannon shells arming themselves shortly after leaving the barrel and detonating just in front of the aircraft - one Nicky Poo was the pilot ISTR