It is a Common Dolphin (Delphinus delphus). The hour-glass pattern on the side is quite distinctive, along with the long, slim beak.
The Bottlenose Dolphin (Tursiops truncatus) has a short beak and a more uniform coloring.
Tom, that's apparently a straight edge to the wound so I'd have thought something has substantially damaged it, before or after death. The massed ranks of 'nibblers' would typically eat out a circular edge. I'm not advocating shark bites or anything dramatic like that though, it probably got run over by the Irish Ferry long after it had already gone to Dolphin Heaven.
Mind you, that JR looks suspiciously well-fed :slap: