I would do the layout of the stand differently, it would be how we originally planned, by that i mean,
The marquis/tent would be central, with the camping area behind it, and the cars all displayed in front.
Had a thought about the llighting on the pitch, we could line the outside with those solar powered garden lights, either the whole pitch, or just the camping area, they wouldnt be too bright, but enough to make it easier to walk around at night, and they are cheap to buy.