Curious Pax, I agree the situation regarding the number of a/c that have to divert from the London airports has changed significantly from the 70s, 80s, and even the 90s. I also take your point about minimum staff numbers having to be maintained at smaller regional airports that may therefore have more opportunity to accept diversions. However, that still leaves several questions unresolved:
I agree that BHX, less than half the size of MAN in terms of pax numbers, may have similar staffing levels - although I suspect less handling agent companies. However, LGW is twice the size of MAN, had its own problems on Wednesday afternoon with delayed flights, very poor visibility with slow arrival rates and a/c having to hold before starting approaches. Yet it was happy to accept the SQ and CX diversions.
Mid-afternoon Wednesday is hardly a hive of activity at MAN for arrivals or departures. Was there really no slack in the system or a can-do approach that would have allowed those two important airlines to MAN to have diverted here when they wanted to?
On Monday, 28th October, MAN accepted a SQ A380, a TG B747 and an AC A330 at a busy time in the morning. Why was it possible then but apparently out of the question on Wednesday?
Maybe as suggested elsewhere, it depends on which manager / supervisor is on duty and who answers the phone when diversion requests are received. Is that really a satisfactory situation?
Whatever logical reasons can be offered, there is a perception that on some occasions (not always), Manchester Airport does not put itself out to offer a a service to airlines having to divert - in this case two of its own rather important customers.