At 1st assumed a land mammal
No interactions present.
Definitely a seal - you can see the flippers in the second photo - and the grey seal's skull is squarer than the harbour seal.
Have just got this book http://www.nhbs.com/mammals_of_europe_north_africa_and_the_middle_tefno_... which has useful skull drawings for most of the species.
OU Certificate in Contemporary Science
Lat/Lng: 51.5703, -4.2933
OS grid ref: SS411882
top of the tide