Identifying a small pale bird

We were at Castle Drogo, Devon, yesterday and outside their cafe we saw a small, sparrow-sized bird with pale (white/cream) feathers. I've attached a couple of images, a bit grainy I'm afraid as I was using maximum zoom on a fairly basic camera. I've tried using the RSPB bird identifier and a more general Google search but haven't found anything that matches (but I'll happily admit I may not have looked in the right place or used the right description). I'd be really grateful if a more experienced member of the community could help identify it as we're really intrigued to know what it is. Many thanks in advance. Phil