Let's just take a gander....
5.5.2 Management representative
Top management shall appoint a member of the organization's management who, irrespective of other responsibilities, shall have responsibility and authority that includes
a) ensuring that processes needed for the quality management system are established, implemented and maintained,
b) reporting to top management on the performance of the quality management system and any need for improvement, and
c) ensuring the promotion of awareness of customer requirements throughout the organization.
1st, it absolutely looks like the MR must be a member of member of management...but isn't it up to the organization to define what management is? Where is the breakoff point in an organization between management and non-management personnel, at the 2nd tier level, 3rd, 10th? In the US Military "management" can go down to the level of an E1 (that's the lowest rank/payscale of any service member in any branch) who has been given authority to over other E'1's, like on a work detail or even in combat. In Marine Boot Camp I was the Platoon Guide, I was senior to all other "Boot's" and exercised management oversight and was held accountable for assigned tasks. The task each organization has is that they must clearly define what does or does not constitute "mangement", and the head of Plant Maintenance could very well fall into that definition and therefore be eligible to be the MR as could the CEO's secretary (Executive Assistant). The decison rests upon "Top Management" and there is no requirement for justification of that decision.
2nd, it looks like the MR is really nothing more than a type of project manager and other than ensuring that stuff is done and reporting some specific information any additional responsiblities are left to the organization to define. There is nothing that states the MR has to do anything other than make sure stuff happens, he/she doesn't have to do the stuff.