longer ron,
Here is the MAA's own Master Glossary. You will see that there was no accident until Flt Lt Cunningham was killed, which as you say was caused by his chute failing to open. The SI itself stated that the aircraft only received Cat1 damage, as has already been pointed out. It would have had to receive Cat4 or 5 damage for it to have been the subject of an accident :-
http://www.maa.mod.uk/linkedfiles/regulation/maa02.pdf
This is not some arcane argument about angels and heads of pins. Rather it is proof, if any were needed, that SIs are still subject to outside influences and cannot be relied upon to do their job. Their job should be to determine accident causes in order to prevent future occurrences. Rather it seems it is to go on protecting VSO backsides at the cost of more junior ones.