UU are working on the dam at Earnsdale (ref 2.5 on route description) and the path is closed at the moment. There are two alternatives with the first being the easier option.

Leave the Tower and make your way to Sunnyhurst pub, then through the woods on the path marked "reservoir" to come out at the far side of the dam and back on the route.

The other is to go down to the Royal pub at Tockholes, make your way across the fields to Fine Peter's farm and then follow the track to pick the route up again.