I'm afraid witness reports from a ground viewpoint can be misleading in the extreme. I would suggest you were perhaps on the inside of the turn viewing obliquely. You can get peculiar visual effects. I had trouble explaining once to my first wife that a very distant contrail coming towards us was NOT an aeroplane climbing vertically! She could not see it. I would say what you witnessed was a visual circuit with a tight turn onto finals (Stockport-MAN about 6 miles=1800'- nothing unusual), maybe a bit undercooked until too late. In approach configuration, the 747 really has its nose very high, and coming towards you slightly after a turn, it will look steep. Any serious transgressions would have been thrown up on the flight recorder to be dissected on the fleet later. I was on the fleet then- it wasn't me and I recall absolutely no such incident!