I've made up some sliding shelves for all my tool boxes but need a solution to restrain them so they don't all slide out when I'm cornering !! Shelves are 12mm on drawer runners, fixed to 12mm tall (about 1200mm high) units fastened to floor and van (ply) lining. At he moment I've fixed a slim piece of 30mm lath to front, but need something a bit more user friendly. Any ideas greatly appreciated.