I'd park near the Church in Otley village and walk from there, through the churchyard and out onto the footpath at the back of the Churchyard. From here it's a pleasant stroll initially through the fields surrounding the village, and then through a little wooded area, after which you'll be at the cache site. The cache is a small plastic box containing Log-book, and (when placed) a selection of other objects; Marbles, Baloons, a Shell, and some Stars. There isn't too many places to hide a cache here, so it shouldn't be too hard to locate.
You do not need to climb under the bridge to locate this cache! You can grab it from the side, though you may need to feel around a bit