Quote Chimbu: "The characterisation of the PIC and the manner in which he was flying the approach in question is a disgrace...how can anyone not on board know how he was flying the approach?"
We know that the PIC or the FO was flying the approach in a manner other than prescribed because of the FLIGHT DATA RECORDER.
We know that the FO did not have an RNAV endorsement.
We know that there is another approach available at LHR that both pilots were qualified to conduct.
We don't know why the PIC elected to conduct an approach outside of the regulations other than speculation shown by his past actions that he regularly operated outside of the rules and was not caught doing it until after he killed everyone else on board.
Lots of pilots and ops people knew this Captain was a regular breacher of the regulations but no-one "dobbed him in" and therefore his life was not saved.