It requires a competent person not a qualified person (unless specifically stated), there is a difference; a risk assessment will highlight who can do what and therefore you can judge who is competent ( working at height training, electrical awareness) upon the findings of the risks involved- training, instruction, information etc etc. Consider the environment and the people/ workers.
I speak as a member of IOSH (institute of Occupational Safety and Health) having worked as a safety advisor -when I say- safe is great but at times we're taking things too far in this country when people start believing you need qualifications to change a light bulb.