The 'intermediate' Hardy Spicer as I've always thought of them, with the 6 bolt fitting, was fitted to late RPs but soon superceded - by the coming of the first Ruby perhaps? Page 52 of the Parts List published in August 1933 here - http://archive.a7ca.org/wp-content/uploads/PL_1029.pdf - shows them. The preceding Parts list we have in the Archive, dated April 1933, shows the Carden block version.
Hugh
Hugh