Gourmet Burger Kitchen, also known as GBK, in Gardner Street, Brighton, has shut permanently. A sign displayed in the restaurant's window (Image: NQ)A notice in the window of the restaurant reads: "Closed. The Brighton branch was among others across the country, including restaurants in London, Birmingham, Norwich and Oxford. The Smash Burger (Image: GBK)In 2018, the restaurant closed 17 of its branches across the country after creditors approved the company’s restructuring plan. According to reports, Honest Burger acquired 12 GBK sites in September last year.