On that basis, some might object to unqualified, non-elected trade unionists from being granted positions of power (by non-elected I mean they are elected only by their members, not the wider public).

To be clear, I don't object to either. However I do believe that the political process is benefited by allowing input from a body of people who can provide the widest range of wisdom, experience and expertise, something our elected representatives all too often lack. That includes both religious and trade union leaders, along with many others.