Hi Steph
I remember the 'closed season' well - no one has taken any notice of that since the early 1980s when there used to be 'voluntary wardens' on site checking permits.
Must have missed you on Saturday, I was on from dawn onwards. As you'll know Barn Owls are very easy to see around Wheldrake (and the rest of the LDV). There are certain times of the year when it's more unusual not to see one (rather than see one). The viewing platform at Bank Island is very good for seeing them, as of course is Wheldrake Ings itself.
Over the weekend there was American Wigeon, Hen & Marsh Harrier, 40 Ruff, several hundred Golden Plover, at least 5 calling Water Rail, over 20 Whoopers, together with the impressive sight of large numbers of Wigeon and Teal, plus there have been up to 3,100 Greylags recently. The reserve itself is hardly watched, amazing isn't it!