In the London film world, there are no golf carts to jet around on, so Tim Bevan strode in and out of buildings, past fields of rabbit warren offices, through editing bays. This is the cobbled-together fiefdom of the once obscure, now powerful Working Title Films, which Bevan and his partner, Eric Fellner, 47, run. In the parlance of Hollywood, they're the Brian Grazers of England, the Jerry Bruckheimers of the British Empire, the producers at the top of the professional heap. Rachel Abramowitz reports.