It's just mighty busy, with alot of well used equipment (although that jetty was one of the newest ones), and also the old phrase - 'Pay Peanuts - get Monkeys' kinda sums up certain jobs at LHR. There is also a severe lack of space for parking equipment, so it usually ends up being parked where it shouldn't be - on the stands, but the BAA won't do anything about it. Each time they build a new extension, they build into the equipment parking bays, then don't provide an alternative place for that equipment to be parked.
Annoying thing about that jetty breaking, was that the battery for the emergency back off mode was flat, so they had to physically push it back off the a/c with one of those electric bagagge tugs !!!. It added a further 20mins onto the 20+ mins Air Jamaica were already delayed, causing my flight to depart over 1 hour late, once it finally got onto the stand (20 mins before std)
"She Rolls, 45 knots, 90, 135, nose comes up to 20 degrees, she's airborne - She flies, Concorde Flies"