Sorry all cannot say away.
The RP is responsible for article 8 to 22 in the workplace which includes the common areas and he will have control of most of those articles, so the workplace is to any extent under his control. Those he does not have control of, a PHC will be responsible for, which doesn't make them the RP’s, as this is a title defined by A3 and not a literal statement. The PHC can be a number of people which IMO does include the owner/representative.
If the RP finds a problem in the common area, say the staircase needs repair, which is not under his control, but the owner/rep. He and his fellow RP’s should try to get the owner/rep to repair it. If he refuses, he needs to be told he is a PHC and the FRS will sort him out or he could be prosecuted under 5(3) as a last resort. (The RP’s need to do that to comply with article 33)
If another RP cause a problem in the common areas then his fellow RP’s should try to get him to sort it out, if he refuses he needs to be told, the FRS will sort it out and he could be prosecuted under the appropriate article, as a last resort. You could also try to get the owner/rep to sort it, even when he does not have any legal responsibility /control and in many cases he most probably would try, however the final action is the big stick.
In chrpay case the RP’s are subject to Art 15 and 22 alone and the RP’s are legally responsible therefore they need to sort it out between them. The owner/rep has no legal responsibility/ control regarding these articles and could get involved if he chose, but I would expect him not to, because I think it an unreasonable request by one of the RP’s.