Interesting - now this will show my technical naivety up, but after reading that I'm surprised it is in focus and looking as sharp as it does. No diss intended!
Cheers for the explanation.
Stu, this effect is deliberate. I got it by setting a slow shutter speed (half a second) and matching f-stop and firing the pop-up flash. What created the swooshing light effect was dragging the camera diagonally from top left to bottom left and firing the shutter half-way through this movement.