Yep I know a little, doubt it's going to help though. It used to be owned by the woman who lives in the house beside it. There is a small river/brook comes out of the lake and flows under the road bridge close to the house. The pool in front of the bridge holds some good trout 1-2lb. You have approx 3 mins to fish (worm) before she sets the dogs loose-they bite! The dogs can be out-accelerated quite easily on a bike providing you hear them coming. Really, if you can get one fish out it's time to leave.
That was how it was 47 yrs ago when I last fished it. Things may have changed

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Some years later around 1970 a syndicate owned the rights. I was passing one afternoon when a man shouted me from a boat to hang on there, I waited and watched as he played a large brown trout. It took ages to land it. Eventually he rowed over and asked me to use his camera and take a photo of him holding his prize...10lb it weighed. I'd never seen a trout so big. He told me his name was Miles and he owned a shirt shop in Wellington and I could have a free shirt for photographing the trout. I must call in some time and claim my shirt. Of if you are reading this Miles-pm me

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There used to be a post office in Sambrook village, if it's still there they will know about the lake. Hth.
Chris.