Need to adjourn a trial on medical grounds? Morgan & Another v Egan  EWHC 1025 (QB) helpfully summarises the key authorities and approach to such an application. See paragraph  of the judgment.
The judgment also sets out the correct approach to appellate review of a judge’s exercise of discretion. See paragraphs  to  of the judgment.
You can read the full judgment in Morgan & Another v Egan on Bailli.