It's important to understand the obligations placed on individuals and organisations by legislation and the responsibilities of different agencies involved in oversight and enforcement of the legislation.
In general terms the HSE looks after personal safety and well-being of individuals in workplaces and the CAA looks after the safety of aircraft operations. More detail of the way that the two organisations work together is available on the
CAA web site.
There is undoubtedly a grey area between HSE and CAA responsibilities where, for example, an impact on an individual could affect the safety of a flight or an aircraft maintenance procedure could pose a risk to the engineer following it.
The principles of assuring the safety of individuals and that of aircraft operations are much the same (i.e. effective risk identification, evaluation and mitigation to an acceptable level) but 'top event' is very different. Nonetheless it's not rocket science but rather common sense to most people.
Like so many things these days, we seem to be trying to turn it all into a science with qualifications for 'experts' who then are the only people who can do 'it'. A shame really, because keeping things safe is in everyone's interest and should just be part of everyone's everyday work - not just the experts.