Vertical centering of the text in table heading

Question

I would like to center the content of table-cells in heading. In guidelines for Polish text documents content of table heading must be centered both horizontally and vertically. I have found such an answer, but I am not able to implement it, because the code is not explained. I tried also application of m-type column as well as \multirow[c]{1}{\mycolumnwidth}{My cell content} and few combinations of them with \multicolumn command. Adjustment of text altitude by \multirow{1}{\mycolumnwidth}[\myyshift]{My cell content} is not a solution - vertical centering must be performed automatically. There is some answer for plain TeX, but I would like to use tabular or similar environment.

MWE:

\documentclass[table]{standalone}
\usepackage{dcolumn}
\usepackage{multirow}

\newcolumntype{d}{D{.}{.}{2.1}}
\renewcommand{\arraystretch}{1.3}

\begin{document}
    \begin{tabular}{|l|d|d|}
        \hline
        \multicolumn{1}{|c|}{\multirow[c]{1}{23mm}{\centering\textbf{Title of side-heading}}} &
        \multicolumn{1}{>{\centering}p{23mm}|}{\textbf{Arbitrary values}} &
        \multicolumn{1}{>{\centering}p{23mm}|}{\textbf{Some other random values}}\\
        \hline
        Description 1 & 63.5 & 48.7\\
        \hline
        Description 2 & 88.4 & 51.3\\
        \hline
    \end{tabular}
\end{document}

Answer 1

With siunitx and makecell:

\documentclass[table]{standalone}
\usepackage{siunitx}
\usepackage{makecell}
\renewcommand{\theadfont}{\normalsize\bfseries}
\renewcommand{\arraystretch}{1.3}

\begin{document}
    \begin{tabular}{|l|S[table-format=2.1]|S[table-format=2.1]|}
        \hline
        {\thead{Title of\\ side-heading}} &
        {\thead{Arbitrary\\ values}} &
        {\thead{Some other\\ random\\ values}}\\
        \hline
        Description 1 & 63.5 & 48.7\\
        \hline
        Description 2 & 88.4 & 51.3\\
        \hline
    \end{tabular}
\end{document}