Probably trashed both engines!
I'm a little surprised that they still have thos plane spotter parking areas at Heathrow ( and probably many other British airports). Some are very near the aproach area ( as you can see from those images) and thus permit
anyone to get closer to the aircraft than most any place on the actual airport.
OTOH, that might be such a good place to perform any dasterdly deeds, either. Especially at Heathrow, there is constant traffic all around there making it fairly difficult to be 'stealthy.'
