I did well a few years ago on Nazeing when the lakes thawed and meltwater was pouring in from the Lee Relief Channel.
Three 20's and a beautiful double on a 4 day/night session. I arrived, walked round, thought I saw a swirl, so set up on it. Within hours I had a 26lb fish, which I nearly lost. The hook pulled, but it sank into the landing net. One blank day, but next I had a 20, and on the last morning another 26, which as I was getting ready to photograph caught the 16lb
Not every lake is the same though. Some will stay switched off until spring, some you may have to find the fish for a bite or two.
The pics have uploaded in the wrong order, it is black jacket 26 first, blue Adidas 20, followed by DPM smock, 26 and 16