\documentclass[british]{article}

\usepackage[useregional=text,showdow,datesep=/]{datetime2}

\begin{document}

\DTMsettimestyle{englishampm}
\noindent\DTMdisplaytime{12}{30}{0}\\
\DTMdisplaytime{00}{30}{0}\\
\DTMdisplaytime{24}{30}{0}

\end{document}
