Hi, the size would be the same as an English size. Â Sometimes, an Italian shoe company would size their shoes using the British system instead of the Continental system. Edit: The Branchini's I recently purchased were sized similarly.
Actually, the StefanoBi shoes that I have run close to Mantellassi's sizes, maybe a 1/2 size smaller than Mantellassi. Frem my experience, new shoe makers like StefanoBi or Mantellassi or Lattanzi rarely use British sizing. Only the older ones do.