Update.
The Health and safety Executive has claimed to both police and judge that the Mk10B parachute release mechanism (scissor/drogue shackle arrangement) is unique to the Mk10B seat in Hawk, therefore witness evidence that both aircrew and groundcrew/maintainers where taught from 1952 how it works, and how to maintain it so that the assembly can disengage, is 'irrelevant'. The fact there is a 107 minute RAF training video, and umpteen servicing schedules from various users, disproving this HSE claim was also deemed 'irrelevant'. Lincs Police Chief Constable has accepted HSE's claim without checking facts. Those on pprune who have actually seen a seat may have a view on this....
Quite why Martin-Baker continue to put up with this is anyone's guess, but oldmansquipper may very well be right. However, the company has now reacted and called forward witness evidence that the HSE claimed to the judge was irrelevant (that word again), despite never having actually spoken to the witnesses or taken evidence. That the HSE has misled the judiciary and police is now the subject of a formal complaint, so that is perhaps a good place to stop....
Someone should write a book.