No James, a couple of years ago Nick Stacey photographed one from the hide that was even closer! I think a couple of people have photographed one in flight there this year too, but pics of Bittern at Greylake are few and far between!

To add a bit more information to this topic. I took 6 pictures of a bittern in reeds and taking flight. The pictures were taken on 29 June 2014, the bittern was in the reeds on the right of the pond in front of the main hide at Greylake.