Flight Safety,
Without any more AAIB input we're back to guessing games....
But your post makes for an interesting question.
What was the fuel flow in m/sec or ft/sec ?
In other words, if it was indeed some kind of obstruction, how far did the 'slush puppie / chinese noodles / wad of chewing gum' travel after being dislodged, to arrive after 3 secs on one side and 7 secs on the other side?
Maybe there's a clue there?
CJ