In 1994 it was decided to split Common Dolphin into two species. One tending to inhabit warmer, tropical, shallow waters was called Long-beaked Common Dolphin (Delphinus capensis) while the other tending to inhabit cooler, deeper waters was Short-beaked Common Dolphin (Delphinus delphis). But there is overlap of range and water depth, and both species occur in the Atlantic and Pacific Oceans, though Long-beaked is also found in the Indian Ocean. This is a Short-beaked Common Dolphin, which is the only one found in British and European waters. They are not especially easy to tell apart, but short-beaked does indeed have a shorter beak, and an isolated eye giving a more open-faced, kinder expression. The stripe that runs from beak to flipper, usually does not extend beyond the flipper, but it usually does in Long-beaked. I photographed this Short-beaked just south of Ensenada at the north end of the Baja peninsula. For comparison here are Long-beaked Common Dolphins showing longer beaks and a less open-faced look:
www.flickr.com/photos/timmelling/52735938074/in/dateposted/