These independently listed writers are not neccesarily reliable, nor can they be considered truly vetted since they pay for their ad placement at this forum.
This is actually true. What's much more important than whether or not a writer (like me) chooses to advertise on the forum is how long the writer has been active here, especially under the same forum S/N. A long forum history, particularly one that goes back almost 15 years, allows prospective clients to review that writer's long-term forum contributions, client feedback over many years, and comments from that writer's colleagues and even legitimate competitors. When I first signed up here in 2008, I purposely used the exact same ID for my forum S/N that was both my writer ID at every essay company for which I have ever written and my email username. That's because my username has always been, essentially, my "brand" name. Long before I ever had any kind of website at all, my email address was my "brand."
Have him write a short portion of the paper you are interested in placing with the writer. See if he can meet your needs.
I also agree with this and have suggested that clients using a new writer for the first time always do this. Ideally, order a short, less-important project with a long deadline before you take the risk of ordering a long critically important project with a short deadline.
Remember that US writers will be writing in a far different manner from a UK educated writer
This is not necessarily true, because an experienced American-educated academic writer can write UK projects that are indistinguishable from projects written by a UK-educated writer. Many of my clients are UK and European students studying at some of the best UK and European universities; and the vast majority of them use me for years, just like their American counterparts.
if you are in the UK, ensure that the writer is up to the writing standards of the UK ... Test the writer well [and] Hire a writer who passes your writing criteria and requirements.
There's no better "test" of whether an American writer can meet UK standards than the same basic test that clients should always use with any new writer: namely, the suggestion to order a short project or a short portion of a larger project before trusting any writer with a larger project. If UK students want to be sure that an American-educated writer can provide high-quality work on UK projects, they should simply test that American writer with smaller projects or smaller portions of longer projects.