Ok, I've made a little progress. Turns out I need version 9.2 of Crossover Games to run RO. Now I get similar results, but if I minimise the window and restore it, I can actually see the interface, but it is extremely buggy, and there is a horizontal mirroring effect, ie, the bottom half of the screen is reflected onto the top half of the screen. Really weird stuff.
Anyone have any ideas?