Turini
Not minding anyone joining our discussion. The more the merrier!
Like everyone has been saying thus far the important thing is just getting the plant named correctly and properly identified rather than who is right about doing it.
So join the party and feel free to give all the ideas and opinions you like.

Looks like a Ferocactus to me, but I couldn't tell you which one.

All help is greatly appreciated!! You're welcome to venture a guess.
Had no idea I provided such a mystery.

A beautiful plant, which is most certainly a Ferocactus.
My best guess would be F. wislizeni subsp. herrerae (following Pilbeam's book 'Ferocactus'), but regular F. wislizeni subsp. wislizeni is also a real possibility. These are readily available at many nurseries here in Arizona.

I note that this and another image of the same plant is still in the database entry associated with the Golden Barrel Cactus - how does one get images that are clearly not correct re-assigned?

Thijs, if you see an image that appears to be in the wrong entry, enlarge the image, scroll down, and write a comment about the image. This will automatically generate a thread in the Plant Photos Forum and will automatically notify the photo owner of the new thread. Many members frequent the forum and join in the discussions, either agreeing or disagreeing that the image has been misidentified. The owner can request that the photo be moved to the appropriate entry. If the owner doesn't show up within a reasonable amount of time, the photo will be moved on the advice of other members.

I am going to propose to move these four images to the generic Ferocactus page until they can be pinned down.