Figures of the Seasons on this scale occur on sundry other bases. I am not at all certain that John Walton made any of the unmarked examples. In fact, I bet they were made by other potters. The figures occur in underglaze colors and enamels, just to deepen the attribution mystery--in fact, I think Aurea's figure is underglaze. I thought you might like to see these two examples in my archive, courtesy of Elinor Penna.
Notice that the two figures above and Aurea's figure all have a low scroll-type structure behind them. Its not quite a bocage, but I am not sure what to call it. I have only ever seen this on figures of Seasons. It occurs on one example of the gentleman-on-skates, the common figure of Winter that we all know best. In all other instances, it is on the lovely large ladies that accompany our lady with the large fur collar. In one instance, it is on a figure of Spring marked Walton.