My money is on the excess of speed and/or height and ATC were probably helping out with a bit of extra track mileage, hence being seen in strange parts of London! (Or he could have been getting too close to a slower one in front).
(Had he intercepted the Glide Slope at 4000', which should equate to 12 miles from touch-down and had he been following a standard Boeing approach profile rather than a minimum noise profile then the gear would indeed be down).