MGM 
I have just made a batch using gluten free plain flour. 
I did a straight swap plain flour for Gluten free plain flour. 
 I used the middle sized cutter. not a good idea as the biscuits spread to large size.  will use small cutter next time. And maybe make them a bit thicker as well     
The biscuits taste  
 
  
The recipe may work better if it is made as a tray bake then cut into fingers - rather than biscuits.  
I have just stated baking with Gluten free so you will know more about the way flour works than me.
Hth