I enjoyed the series, and the books, for different reasons.
I always like David Jason as an actor, and he played a thoughtful old-fashioned 'copper' in the series who disliked any mention of his George Cross for bravery. I enjoyed the series until the last one or two which were identified by the re-done coiffures of Frost and his oppo, all slicked back and modern, and the series went off the boil for me at that time.
In the books, Frost was an 'of his time' copper, not shy about being crude and sexist but every bit as determined to get his man, and avoid filling in his expenses!