I moved to Great Ellingham in Norfolk about 5 years ago and i've always known about a fishing complex called Swangey Lakes just down the road.
Only yesterday did i find out after a good mornings birding there that it is in fact Swangey Fen SSSI (site of special scientific interest).
Here's a link to what makes it special.
It is a series of large lakes. Over 5 i think. I haven't found them all yet.
So far i've recorded
Black Headed Gull
Great Black Backed Gull
I haven't yet spent a whole day there so the list could grow, especially as i haven't studied the reeds yet.
The river Thet runs through the site as well
Its well worth a visit.