Minton posy vase, 1976 - design info?

Curious to know if anyone has come across this design before?
Marked Minton OA.1976, the painter is simply a question mark, even though it's finally drawn with pink and green enamelled panels, done by hand (the photos don't do justice to the finely stippled shading). It must be someone with a very steady hand.

I'd think it may have been a blank someone bought to decorate themselves.

Maybe, although last night I found something similar (hand drawn horse and rider with pink and greeny-blue enamel decoration) on ebay last night described as having "OA-1978 with Minton backstamp and two decorators marks" so maybe it was a test piece for a new range that didn't get into production because of the time it took to complete each piece.

Further to the original post, here's the other Minton posy vase.
Same colour enamels, but the pictures are transfer printed rather than hand drawn, which suggests the first one was a trial piece. There are some gaps in the lines which suggests that they would have had production problems with an overly complicated design like the first one.

Original photo was a bit yellow. Here's a better one.