Having seen a lot of these, including one that Jonathan Horne sold that is clearly of British manufacture (now in the Longridge Collection), I now conclude that most were made in France or possibly the Netherlands and would front a kitchen type clock hung on the wall with the works hidden behind the faces. They often have later drilled holes, like this one, above and below the central hole.
Diameter: 9 ½”
Condition: Besides the two afford mentioned drilled holes there are three significant chips to the rim on the back.