What determines when a criminal case’s sentencing remarks are available publicly or even exist in written form in the first place?
Regarding written remarks, this word doc answers a Freedom of Information Act request:
What criteria do you use for deciding whether or not to publish judgments, rulings and sentencing remarks on your website and Twitter?
Publication of judgments, rulings or sentencing remarks is undertaken by the Judicial Communications Office on behalf of the judiciary. These are published on the Judiciary website, and highlighted through Twitter, if the nature of the media or legal profile of a case suggests it would be helpful.
The majority of cases are publicised because of the actual or predicted level of media interest. In some instances, however, the Lord Chief Justice or another senior judge might flag a case as one that gives specific guidance on legal issues such as sentencing. Publication of sentencing remarks from Crown Court cases is again generally governed by the level of media interest, but will also depend on them being available to us: it is important to note that not all judges have full written script of the remarks they make at the time the sentence is handed down.