Bursley Ware - Rosemarie pattern. Any info?

Hi there,
I’m struggling to find any reference to this pattern given as ‘Rosemarie’ on the back of a set of demitasse cups, saucers, creamer and sugar.

I was interested to know the approx date and if it could be appropriated to a designer.

The blue is transfer print with a green hand painted wash and hand painted orange petals.

There are no other impressed marks, just what I assume is the decorators mark (possibly a B) as it is the same orange as the petals.

Any help much appreciated.

Thank you!
Jen

Thank you, that’s very helpful re date.
I can’t understand why there’s nothing on ‘Rosemarie’ could it have been a pattern that didn’t go into full production perhaps?