[Numbers in circles]

I am brand new to Affinity, so I hope I haven't missed something obvious.

 

I want to place numbers on photos to be able to reference them.  I have down loaded fonts that have numbers encircled with a outline.  Both black numbers in a white circle and white numbers with a black circle.

 

I load a photo as background layer, then add text layer and insert the circled number I want using the font.  The white part of the image is transparent and the image from the background shows through. 

 

Is it possible to use these types of fonts to number photos keeping the white portions white and not transparent?

 

Thanks