The other feature that is equally puzzling is the treatment of the base and the stem and the lower part of the bowl. At first glance they also appear to be engraved. But when you feel the surface of these areas, they are raised, suggesting etching, or even more unusual, possibly having been part of the mold itself. It may also be that the engraver cut away in the "negative". In any event it represents some of the greatest ingenuity and talent, and worthy of every moment of awe they get.
There are some closeups of different parts of the goblets. Notice the incredibly fine cutting in the large flowers, and the tiniest scales above the upturned "leaves" in the base of the bowl.
These were confirmed as Hawkes in a series of sales. See the green wine stems below––most were marked Hawkes. Mystery solved!