Kent Constabulary is not bucking any trend here: it is one of three Constabularies, along with Cheshire and Cambridgeshire, which have received low ratings in the latest reports published as part of HMIC's rolling crime data integrity inspections:
http://www.justiceinspectorates.gov.uk/hmic/our-work/crime-data-integrity/
Forces receive one of four overall grades: Outstanding, Requires Improvement, Good or Inadequate. 10 reports have so far been published: none Outstanding, 2 Good, 3 Requires Improvement and 5 Inadequate.
Kent, Cheshire, Greater Manchester, Merseyside and Devon & Cornwall were all told to stand in the corner of the room and fight over the pointed hat with a large 'D' on it.