If conditions are good for stalking, then leaded (or tungsten) bugs, nymphs, buzzers will be good for targeting individual fish. You need to get the fly down to the right depth quickly - otherwise the fish will be long gone (depth perspective in the clear water can be difficult).
I've had more success in the second lake (nearest the entrance). I understand both lakes had been fishing quite well.
A word of caution - I understand both lakes are suffering from algea bloom and surface weed making fishing very difficult indeed. This is second hand information heard from several anglers arriving at Avington over the last 10 days or so having declined to fish Dever. (I've fished Avington four times in the last two weeks). This should be a temporary problem and I'm sure the management there will give you an up to date and honest report.
Neil
http://bigrainbows.blogspot.com/