Park in the little car park at Cow Bridge, and head up the track along the shore of Brother's Water. At Hartsop Hall, take the right-hand track that slopes steadily up the side of the hill.
Just past the waterfalls turn left and follow the stream steeply down into the bottom of Dovedale; cross the stream on the footbridge, and head back to Hartsop Hall.
From there, retrace your footsteps to the car park.