It's good to be back handling Barn Owls and the early visits are always interesting as you get a chance to see more adults. Here are pics of a pair from a box near Stathern. Other things that help to sex them are the whiter tail of the males and of course the female had a whacking great brood patch. (Click on the photo to see a larger version.)
The female was in moult as can be seen from the uneven primary tips in this and the next picture. Although most birds wait until breeding is over before undergoing moult, Barn Owls often start during the breeding cycle. Thanks to Ian for the pics.