Which seal? And which gull????

Two days ago Limpy and I found ourselves at Winterton, Norfolk - it was suitably gusty and a variety of gulls were doing their thing.  Happily, the seals were also showing - but I haven't got a clue how to tell a grey seal from a common one.  I do have a few photos:

I also got this gull, which appeared to be white-winged.  Is it a Mediterranean?

My only excuse is that I'm not used to seeing Meds out of their breeding plumage.

All help will be gratefully accepted!

Our herring gulls are red listed birds.  Think about that the next time you hear some flaming idiot calling for a cull of them.