Interesting snippet from wikipedia a out John.
As a player, he was a right-back from 1987 to 2007, spending his entire 20-year playing career at Grimsby Town, and holds the club's all-time appearance record, having played 647 league games, 754 games overall for the Mariners. He is one of only 17 players in the history of English football to play more than 600 Football League matches for a single club.[citation needed]
Upon retirement McDermott moved into coaching at the Grimsby Institute before he was appointed assistant manager at Harrogate Town in 2010.[1] McDermott was appointed as manager of Alfreton Town in May 2017. He mutually agreed to part company in 2018.
In July 2007, McDermott applied for the vacant manager's job at Boston United but was overlooked for the position, and United in turn appointed Tommy Taylor.