names
Prominent figures can just be named in stories, with their function at second mention: “George Osborne said last night ... “ (first mention); “the chancellor added ... “ (subsequent mentions)
Where it is thought necessary to explain who someone is, write “Chris Wilder, the Sheffield United manager, said” or “the Sheffield United manager, Chris Wilder, said”, etc.
In such cases the commas around the name indicate there is only one person in the position, so write “the Labour leader, Jeremy Corbyn, said” (only one person in the job), but “the former Labour leader Neil Kinnock said” (there have been many).
Do not leave out the definite article in such constructions as “style guru David Marsh said ... “ It should be “The style guru David Marsh” (if there are other style gurus) or “David Marsh, the style guru, ... “ (if you feel only one person merits such a description)