I am a master's student in physics, from outside the UK and I'm not familiar with the academic hierarchy/titles in the UK. I am working (remotely) with an academic from a prominent UK university, and we have been collaborating on a project for a few months now. I found out about him, through an advertisement for a PhD project listed on the university website. I did not get the position, but the project we are doing is different. In the past few months in interacting with him, he has also told me that he is looking to take PhD students in the next admissions cycle.
Now, I am unable to find him listed as a faculty member anywhere on the site. For example, he is listed under 'Research Staff' not 'Academic Staff' but he has also been awarded a prestigious fellowship. So under his webpage, it just says 'X Fellow' (not revealing the title for confidentiality), and it neither says postdoc, nor does it say reader or something, which I've seen commonly in the UK (in fact there are other people listed as postdocs under research staff as well). On his webpage in a field-specific research repository site, he is listed as a 'Junior', but I think this is a self-filled webpage.
How do I check if he is a faculty member or not? I'm confused since it is not officially listed anywhere (except for that research repository site) but the university has advertised PhD positions with him as the (sole) project supervisor.
Are 'research staff' in the UK at the same level of the academic hierarchy, with the exception that they don't teach?
The reason I ask is because I intend to ask him for a letter of recommendation when I apply for PhD programs again, and if he is 'officially a postdoc' then I'm afraid his letter may not be weighed equally with that of a faculty member. I'd also like to work on a PhD with him, but if he is not a faculty member, then I'd hesitate to apply to his project, should a project be floated under him again.