To get there you have to go to junction 10 of the A45, turn right at the roundabout, go over the bridge and go down the little track on your right as you cross over it. The track is long and you may, or may not, need a new suspension by the time you get to the end of it.
The most annoying part of fishing there was the track. Not because of how rough it is, but because of the tedious pace you have to drive at, unless you have a 4x4. Which is excruciatingly frustrating when you're only about 500 yards from the lake.
It used to take me almost as long to drive down the track as it did to drive the 20 miles from my house to the start of it.