It's multicar racing not totally unlike the Btitish GT Championship - anything from little saloons to V8 Supercars. They only run one 24 hour race I believe, the rest are a couple of hours. Can't seem to find a website for it though - they get quite a lot of coverage on Dailysportscar.com.
"Bintcliffe's done it again and the car's f**ked." RIP David Leslie.