You're right, Snows, a quick Google comes up with 'green shoulders'!
I'm still looking at our 'Shirley' toms, which, while they're beginning to ripen, some have small green spots on the skin. The inside is just fine, and they taste OK!
I might try 'Red Alert' next year, as I originally thought they were just an old - nearly Heritage - tom, but looking at their spec, they could take over from 'Sungold' as a nice early cropper! Trouble is, they're a bush type, so may muck up the GH somewhat...