For a movie depicting a young man's struggles with sex this movie is mostly passionless, and that is what weighs it down. I would have put the father more into the background too even though Trevor Howard gives a strong performance. Dean Stockwell is also good as Paul, conveying the intelligence and confidence yet confusion of the main character.
If the film had been made a few years later more could have been made of the Lawrence book on which it is based. His Lady Chatterly's Lover was being un-banned the year this film was released. Is that The Battle Hymn of the Republic being used (ironically) in a scene after one of the Morels' rows?