Posted by Brian on August 29, 2012, 9:30 pm, in reply to "confused"
The occasion was the christening of Prince Richard, held on 20 October 1944, which does eliminate the Flower Basket brooch. The Jardiniere remains a possibility.
To my eyes, this brooch appears to have a somewhat regular semi-circular shape which led me to wonder about the possibility of it being one of the Cartier clips.