There are two types of Seal normally found on the UK coastline - the Harbour (or Common) Seal and the Grey Seal. I'm not an expert, but I'm pretty sure this is a Harbour seal, as it has close set nostrils. The Grey seal has a more pronounced snout, with relatively wide-set nostrils.

This is the sort of view you'd get if you saw the seal swimming, they don't tend to show more than just a head, looking around...

Harbour Seals tend to be the ones that haul themselves onto a rock and lie in this characteristic banana shaped pose...