The only downside was that a huge air bubble got trapped just under the top crust - resulting in a huge, swollen loaf which came bursting out the tin. When I sliced it open, it was like a big cave, inside the bread. I am not sure how to prevent this happening again.
Then again, it wouldn't stop me doing this bread again. When you eat it, you don't think, "ah, beans" - it just tastes nice, and had a satisfactorily chewy texture.