Really do not find these critters easy to identify.
No interactions present.
I agree that this photo is more difficult to get an ID from than the others, but I'd still say the shape of the profile is more concave than straight so therefore common seal.
OU Certificate in Contemporary Science
Both species are found in the waters around Shetland, though the grey seals are most common.
With this one the angle is difficult, however the nose is very clear. Ignore the forehead, look at the nostrils. Again it is unfortunate they are flared but even so you can see they clearly do not meet at the bottom, they are more parallel than 'V' shaped. I'm afraid this is a female, or more likely an immature grey seal, they have a slight concave 'Roman' nose - the adult males are convex. The markings (dark grey with blotches rather than spots) and cranium (domed) shape are more grey seal as well.
If you want to put up a revised identification I'll agree to it.
Visit the iSpot Yorkshire forum for information on events, issues and news relating to 'God's own country'
Lat/Lng: 59.991182, -1.275456
OS grid ref: HU405231