Ok got it!
Heading out of town on the M32, get off at junction 2, go up stapleton rd, it takes you back under the M32.
It changes name to Bell Hill then Park rd, but it's all one straight road.
Turn second left after the garage into Duchess Way, if you get to the small roundabout you've missed it and gone too far.
From Duchess Way turn right, then immediate left into Countess Walk.
You have arrived!
Go to the end of Countess walk, it is then grass (it's a bit of a walk but not too far), head right into the far left corner, which takes you under the M32, go left and the lake is elavated on the right.
Good luck mate.
Steve