Gimbels was a major American department store chain (founded 1887, Indiana; flagship in Philadelphia, later NYC). It never operated in the UK.
Liverpool's historic department stores included Lewis's (1856–2010), George Henry Lee (now John Lewis), Blackler's, and Owen Owen. Gimbels' international presence was limited to a few U.S. cities and a short-lived Puerto Rico venture.
If you recall a Gimbels-like store in Liverpool, you're likely thinking of one of the above—or perhaps the fictional Gimbels from Miracle on 34th Street (set in NYC).