I am unsure if you ever got an answer to your question, but Sidney Lawrence was Chief Constable of the Kingston upon Hull City Police, from 17th January 1948 to 30th June 1962.

He was known as a disciplinarian and was hated by most of the men.

In the 1967 Police & constabulaey Almanac, he was still the HMI for the north west, based in Manchester.