Rather than just telling you that there are Mediterranean Gulls in your shot, I've taken the liberty of copying & annotating one of your photos to give you pointers for next time. It's always better to know how we know!
Note that I've only dealt with summer plumage adults. In brief winter adults are similar but have a white head with a dark mask and the 'ghost' of the rear of the hood, 2nd year birds are like winter adults but have black markings on the wing tip (but in a very different pattern to BHG) and immatures are like contrasty young Common Gulls.
Wow, thank you, John! That was really a Masterclass. I'm not used to seeing Mediterranean Gull a lot, that's why I was hesitant, but I'd know how to tell it apart from BHG next time. Thanks again for the great feedback!
Thank you also Chris for the remark, and Alexander, for pointing out the rest of the species. I had actually missed the tern in the photo when I first saw it. But it's clearly there. Great feedback guys, much appreciated!