Check in your boot. If you can smell it in there check the filler pipe for splits and the clips for tightness (you will have to remove the metal cover). Mine stunk of petrol after I extended my filler pipe and it turned out to be one of the clips was not tight enough and fuel was spilling out.
Also check where the fuel line feeds into the injector rail and the overflow back out. Mine has the dual feed rail and the previous owner hadn't been particularly good with the jubilee clips, hence petrol flow out of the return feed. The smell was so bad that other people at traffic lights were getting out of their cars to check they didn't have a leak. 2 good jubilee clips fixed it easily.