I have read over the VM response several times in an attempt to get my head around the actual meaning of what is being said. Unfortunately I have failed in that respect in fact the more I consider it the less sense it makes and just dissolves into gobbledegook.
To be clear apart from a requirement to provide relevant information they should have no further part in the proceedings and no further contact with the OP who should be guided/represented by his solicitor or other professional.
If not done already a wise move may be to contact the Citizens Advice Bureau who provide accurate and free advice from specialists in a wide range of issues. The local branch should be contacted by phone or email in the first instance.
There is also the existence of the Health and Safety Executive who in the main deal with accidents and fatalities in the workplace so I am unsure if the circumstances of this issue would fall within their remit. This can be established by a quick (hopefully) call to their advice centre on 0800 0294381 and if nothing else some relevant guidance may be gained. Presumably the mantrap setter was in his 'place of work'. .
A specialist solicitor may well give a short initial consultation free of charge to assess the circumstances.
The main thing here is do not allow VM to influence you or take any level of control in this issue - you are in the drivers seat - it is a concept that VM will have difficulty with or even comprehend.
Good luck with it