Surely, if M-B had known that the RAF would be undoing and retightening that bolt so often, they'd have taken a simple engineering step to prevent the shackle being pinched?
This undoing/retightening was carried out as part of a Routine Technical Instruction, issued by MoD.
An RTI is only permitted if the Design Authorities (Martin Baker and BAeS) do not need to be involved in any way whatsoever. A 50 hourly regime on a safety critical escape system most definitely does not fall into this category. Therefore, it is unlikely Martin Baker knew of the RTI, or if they did know they were excluded from the process. As I mentioned before, this has resonance with the illegal Servicing Instruction issued by Odiham on Chinook HC Mk2 and was in all likelihood considered necessary by one part of MoD because another part had cut funding, thus preventing Martin Baker being involved.
If any action connected with this RTI forms part of the HSE's case, then all Martin Baker need do is table the RTI and demand that the signatory be a witness, to explain himself.