Deborah Singleton a k a Bee on YouTube. A very similar report was passed to a Bigfoot group on Facebook in the early 90s.I wonder whether this account should be considered as a British Bigfoot sighting, although later commenters on that thread try to tie the apparition in to Kirkstall Abbey, which is a couple of miles to the east. It's a stretch of road I frequently travel on, and I walk the dog on the riverside path at that point, too. So it's of slightly more than academic interest to me, this one.
ETA there are actually three bridges in quick succession along that stretch of the A6120: over the railway, the river Aire, and the Leeds -Liverpool canal, in that order as you come down the hill from the Horsforth roundabout mentioned. Perhaps unsurprisingly, the River bridge is the one in the "dip of the valley".