Security aren’t responsible for supervision of contractors, they allow access ensuring they are signed in. I wouldn’t expect a security man to know RA/MS, the extent of the works or to check if they have the correct qualification to be doing what they are doing and working in accordance with the HASAW act 1974. A security man won’t escort them to their place of work, they will tell their point of contact on site to do that and show them the welfare facilities and a site induction for escape purposes. If they make security a scapegoat, then they truly are taking the piss.