'but any uncle tom cobbley amateur,can be allowed to do a review.'
You rightly cite Roy Harris as one of the most trustworthy reviewers around. When Roy was moving to Cardiff he recommended me to The Nottingham Evening Post to take on his role as folk music correspondent on account of my involvement in the music and past experince in a similar capacity. However it wasn't as easy as that; a seaching interview with the Features Editor allowed me a few weeks trial. This few weeks is now sixteen years of following Roy, so presumably I'm doing something right.
I also contribute to a local, on-line magazine where none of my fellow contributers receive a brass farthing yet they take an immense pride in their work; ask the many professional singers and musicians who have had their work reviewed in "Tatters"
Finally I might suggest that there are a Hell of a lot more "Uncle Tom Cobbley amateurs" who have the wherewithal (but not the talent) producing their own albums for critics/reviewers to worry about.