You're right about Grace Jones. It makes me wonder if the African cast of the features is intentional. I'm calling it an angel because that's how it's labelled in the Museum, but the more I look at it the less likely that seems.
There was a TV programme the other day where they were doing a forensic examination of a skeleton from the cemetery of an English medieval monastery. Its owner turned out to have originated in North Africa. It seems quite a few Africans may have come into England in the retinue of returning crusaders.
I think what looks like close-cropped hair is a veil. You can see the edges of it coming down on either side. In which case, she's a woman, not an angel. Androgynous as they were in the iconography, they were never shown in woman's clothing.
The face remains intriguingly non-European. And full of character.
I used to think the Reformation had made a clean sweep of medieval art, but there's still a lot around if you're prepared to go looking for it. I was at Howden Minster last year- an unsung, big church in rural Yorkshire- and it has a remarkable collection of unbroken medieval statues.