Hi EGCC,
Not sure about this one, its only a guess because I didn't see this happen. A while ago, a Lufthansa 737 was on approach, finals at about 2 miles, when suddenly he veered off to the right, maintaining alitutude of about 900feet whilst doing a small circuit to the right... the reason was that he was too fast and was losing speed. It was quiet at the time, and it was a year or so ago, but I suppose its a possibility... instead of a full GA it could have just been a loop. Bet it gave Woodford a fright!
G-BPEC