vladimirjp: Thanks, I didn't understand at first because as I said initially, ramping up the light value from the whiteboard washes things out. After a bit of experimenting, I'm guessing that didn't happen in your render because you moved the whiteboard further away to compensate.(?)

BMS: Thanks for the file. I learned a lot from looking at it.It looks nice with the camera environment color right up to light the scene. It does tend to lose the shadows though.

But thanks guys, by fiddling with both solutions I've found a middle ground that works well