That book can be found here: https://archive.org/details/progressofdoctri00ber
It is by TH Bernard, not William Kelly. James McBroom also quoted from it.
Does anyone know more about Thomas Dehany Bernard [1815-1904]? The basic information about him is in the DNB, but for someone whose Progress of Doctrine was cited repeatedly by Brethren writers, we seem to know very little. Timothy Stunt