From a trip to Malham in the Yorkshire Dales in 1950, quite possibly Youth Hostelling.
Not really sure where this waterfall is, as a quick Google search for waterfalls in Malham doesn’t come back with anything looking much like this. It would seem that Malham is close to Gordale Scar (it’s not an area I know at all), but there is a different photo that looks like the waterfall there. Any ideas anyone?