I am wondering too, if LHR should have been shut for so long. I understand the immediate concerns of supervisors dealing directly with incident(s) but what about the wider operational issues? Are decision makers aware of many operators fuel policy, such as dispensing with alternates? If any diversions involved Pan/Mayday calls, it means that the closure decision generated emergencies in its own right. To have large numbers of aircraft with low fuel states diverting is a serious matter in itself.
Strange as it may seem, most airports have what we, in Army Aviation, called a "Pre-Accident Plan" that carefully scripts the response to emergency situations. In developing the plan for the two airfields I was fortunate to command, these very items were addressed, as the directives for a Pre-Accident Plan required it. Each player in the response plan is given specific duties and responsibilities, and rehearsals and dry runs are held to keep the players current. At one of those two airfields (actually a very busy heliport with a typical population of 80 to 120 aircraft tenant on the field), our plan was coordinated with the nearby commercial airport (3.1 miles away) and the National Guard F-4 squadron there, local civilian fire departments, hospitals, ambulance services and ATC.
BTW, part of that Pre-Accident Plan was a direct link between our Range Control Office and civilian ATC to provide for shutting down all artillery firing to enable the massive restricted area to be released to civilian ATC as available airspace to make handling an emergency a bit easier.
I am quite confident that when the fire brigade at LHR was launched, it involved a hell of a lot more agencies than one would initially imagine, executing a well thought out, pre-determined plan that addressed virtually all the contingencies being worried about here. There really are intelligent life forms out there beyond the wing tips.
