Complex sentence: The head of this part of the Department is the Queen's Police Officer, whom is the senior Personal Protection Officer to the Prince of Wales, holds the rank of Superintendent, while most Personal Protection Officers are Inspectors or Sergeants.
Split into simpler sentences: The head of this part of the Department is the Queen's Police Officer. The Senior Personal Protection Officer to the Prince of Wales is a Superintendent while most Personal Protection Officers are Inspectors or Sergeants.