Bigbusdriver
I don't work for BA, but you describe what typically happens when one thing goes wrong and leads to a load of other problems.
Agent brings pax at wrong time; doubt that was at the request of the operating crew.
A/c found to be overweight. Well I doubt the crew planned it that way. It may have been tight on that particular day and they would have planned with the figures they had at the planning stage. To find that the real figures on the loadsheet are different is not something the crew had any control over until the loadsheet arrived.
A/c then found to be overweight so crew did the only thing they could do; offload something, in this case the freight. Once again, you can't necessarily blame the crew who would not have intentionally planned to be overweight requiring a delay to offload weight.
Getting someone to offload the freight doesn't happen instantaneously. Depending on what you are offloading, it may not be just inside the cargo hold either, requiring a bit more 'rooting' to get it out. This all takes time, especially if another piece of freight needs re-securing afterwards.
Missed slot. Well that's what I mean by a knock-on effect when one thing goes wrong. Crew would have maneged this with their operations as expeditiously as they could and the option to cruise at a lower level obviously meant minimising the delay.
Another example of a knock-on effect is the low level cruise leading to a long range cruise due limitations on fuel, again a curve ball thrown at the crew who obviously did everything they could to minimize the dealy.
20 minutes to cross the runways at Heathrow? Perfectly normal and I don't see how your friend can complain about this, especially as it is not down to the carrier! Completely unrelated issue.
15 minutes for a gate? Well, Heathrow is overcrowded and if a spanner goes in the works anywhere it can quickly lead to chaos. Perhaps the carrier could be blamed for this though, but certainly not the crew. Parked on a remote stand? So what? Would your friend rather have sat on the aircraft for longer waiting for a gate? Again, the crew were just making decisions based on what happened.
T4 a zoo? Yep, agree. Answer? T5.
So I think perhaps your friend should complain to the carrier about the level of service, but should also commend the actions of the crew on the day who (by the sounds of it) did a great job dealing with the various problems.
PP
p.s. I know you never pointed a finger at the crew in question, but the title of the thread seems to ask about who operated it.....