What about mosaic tile? Lots of colors, styles, sizes, and finishes to choose from. You can also mix tiles or keep it simple and uniform - whatever you prefer! This fireplace was done in a single color of iridescent tiles, very sleek and modern! (other colors available!)

I have just taken a couple more pictures (excuse the untidy house) from the stairs. As you can see it's an open plan area that isn't that big but very high ceilings also in wood (Macrocarpa) with dark wooden beams. The house is surrounded by bush so quite a dark house. I initially considered a darker wood similar to the beams but not sure if that will make the house appear smaller / darker...I'm really not sure what to do!?!?!? Thanks

It's really nicely done, maybe just some fresh cloud white paint from Benjamin Moore? It really adds a lot of texture and interest.

Could you post a picture?