Danger - No path beyond this point
You cannot see the waterfall, which is the icing on the cake of the ravine, without taking the path upwards from the last of three footbridges, where there is a clear warning about proceeding. This isn't a route for people who find heights difficult. Good, grippy walking boots are very helpful.
Frank Duerden, in his Best Walks in the Lake District, describes a Stanley Ghyll route that takes in St Catherine's Church on the return leg. It's very much worth it. I bottled the stepping stones, but a quick walk upstream brings you to a girder bridge - you don't, as Duerden says, have to retrace your steps.