Not as much....
The debate around the competent person is not just that they be competent, but also impartial. For some forms of violence, it could be the case that two members of the committee actually make up a competent team. When one of our flight attendants gets assaulted on an airplane, we may not have to go external. Two members of the health and safety committee could bring enough skills to form that competent person team, with two people, an employer and an employee, doing the investigation. That could be sufficient to meet the competent and impartial level.