The original cover for Sunliner was, to be honest, pretty poor. It lacked any real hint of what the book was about or anything that might draw prospective readers to it. I kind of thought at the time that it was quite subtle and classy looking, but Sunliner is a book that is neither subtle not classy (deliberately so).
So, I had another bash today and have come up with v2 which is still not perfect but does at least have a car on it and therefore some sort of tie back to the story.
I'm also thrilled to be able to say that someone with far more talent than I has offered to design a cover for me so with any luck I'll have something much better to slap on it before too long. :-)