SHJ, take a look at FR24 when Stansted is using 05 - you'll occasionally see aircraft approaching from the south via Eastbourne or Selsey route across London at about 16000' and then descend towards Royston (Barkway?), turn right through 180deg towards Hoddesden, then left and left again on to base leg and final approach. Ryanair and easyJet are regular users of the route.
Presumably the dog leg is to fit in the necessary descent while keeping clear of Heathrow traffic.
Cheers
Treadders