You've no worries Griff, it was me assigning the effect to player ships without realising it would have an effect which was causing the crashes.
I have left, out of interest, your script attached to various sub entities to see if it still works, nothings crashed yet. I was curious if the effect could be applied to larger subentities such as the Lampyrius boot (and any larger parts of bigger vessels that are counted as sub-entities) without the same crashing, unfortunately I haven't come across one since to test this so it may be stopping those vessels from appearing, but this is pure speculation.
I'll keep it set up this way for a while, and if none of them appear I'll say something about it, otherwise, don't worry.
The only change I would suggest so far is that the amount of parts spawned are related to the size or mass of the object.
It would then be possible (I think) to attach the effect to all subentities too, with only the larger scoopable parts appearing with destroyed engines/cargo holds, even stations. Some of the smaller ships don't need half as many that appear.
If this is likely to slow down the spawning of the parts then perhaps this could be preset individually for vessels/subentities in the addition that is made;
<key>script</key>
<string>griff_explosionScript.js</string>
(<quantity of parts spawned for this assignment-under certain amount no scoopable parts>)
Is that possible or uneccessary?
EDIT This is very good you know, makes it much more satisfying especially when your in an up-close chase and all the bits bounce off yer bonnet