I remember pilots checking for a loose fit on the shackle, basic stuff really
I can't, and so never, comment on what pilots should or shouldn't do, but this seems sensible. What I would say is it should have been the umpteenth time it was checked. As East Street says, there is a cultural aspect to this which the SI report is remarkably frank about, even though elsewhere it fails to properly assess events and factors. This makes it all the more puzzling why the HSE are going after Martin Baker.
But the "enormous paper trail" is what allows you to identify where the breakdown took place. The Secretary of State also requires it before allowing the aircraft to be flown. There has clearly been multiple breakdowns and that should concern everyone, because the system is designed to withstand failures (checks, double checks, defences in depth). THAT is where senior staff never allow inquiries to go.