There was apparently a weir here from the time of the medieval abbey, but it was rebuilt in its present form in the early 19th century along with the adjacent sluice gates that supplied downstream mills.
The weir, sluice and keeper's cottage are together listed grade 2 (list entry 1255851).
The "granite setts" were probably whinstone quarried from here NZ5611 : Cliff rig quarry.
The quarry was owned by the Leeds Corporation and it's supposed that most of Leeds streets were cobbled with Great Ayton whinstone.