Due to bad weather it was very late in the afternoon before I went out to the river to check on the birds. At the nest site, right there in front,was a Heron. These birds are lethal predators and in fact, Britain's largest predator and If I were a Dipper I would keep a low profile and avoid a Heron like the plague. So I wasn't surprised when the birds stayed way up river and didn't come anywhere near the nest while I was there. I did video them feeding though which didn't turn out too bad considering that the light was quite poor. Here is a link to the blog entry and the video.
http://parrotletsuk.typepad.com/wldlife_in_a_suburban_gar/2011/03/ring-flash.html