I was thinking of the Four Seas collection. It might have been one that was exclusive for collector's club members. This is an image of a (smaller) North Sea.
https://www.pinterest.co.uk/pin/four-seas-isle-of-wight-studio-glass--552183604290255737/The strapping is kind of marvered flat towards the base, but left round and proud towards the top, which adds a a perspective.
All the Four Seas and Night Sea seem to be very similar. Variations on a theme.

I can't find Four Seas on Anton's site.
As is the way of things, when one question only raises more, or you find something of interest along the way, the word vitrigraph appeared on that link. Never heard of it. Looked it up.
"What is a Vitrigraph?
Vitrigraph comes from the Latin “vitri” (glass) and the Greek “graph” (writing). A vitrigraph kiln is used for the process of heating glass in a small pot and allowing the glass to flow out of the bottom of a pot through the bottom of the kiln."
