book won't do it, directly.
Without re-programming styles (good to know how, though):
As mentioned in the comments, for a light sprinkle of case material in a text, use the jurisdiction bib entry type in combination with one of the oxnotes biblatex styles.
Put the whole medium neutral citation in the number field.
@jurisdiction{rvsheppard2,
title = {R v Sheppard and Whittle},
number = {[2010] EWCA Crim 65},
institution = {CCA},
}
Use autocite in the text, so that the case reference goes into the footnote.
If you need to refer to a case name in the text (why?), use citetitle.
To pull a case reference into the text, use fullcite.
Use textcite for books.
And if you're feeling particularly adventurous, you can co-opt the fields of a paper-print report jurisdiction entry to display the MNC correctly, using the date, journaltitle, pages, fields together with the options = {year-essential=true} setting.
date = {2010},
journaltitle = {EWCA},
pages = {65},
options = {year-essential=true}
MWE:
\RequirePackage{filecontents}
\begin{filecontents}{\jobname.bib}
@jurisdiction{rvsheppard,
title = {R v Sheppard and Whittle - xxx},
date = {2010},
howpublished = {EWCA Crim 65}
}
@book{av,
title = {Aardvarks},
date = {2010},
author = {A Author},
punlisher ={XYZ Books},
}
@book{zz,
title = {Zebras},
date = {2016},
author = {Z Zuthor},
punlisher ={XYZ Books},
}
@jurisdiction{rvsheppard2,
title = {R v Sheppard and Whittle},
number = {[2010] EWCA Crim 65},
institution = {CCA},
}
@jurisdiction{rvsheppard3,
title = {R v Sheppard and Whittle},
keywords = {en},
date = {2010},
journaltitle = {EWCA},
pages = {65},
institution = {Court of Criminal Appeal},
options = {year-essential=true}
}
\end{filecontents}
\documentclass{article}
\usepackage[
style=oxnotes-ibid,
firstinits,
backend=biber,
sorting=nyt,
natbib=true,
maxbibnames=99,
maxcitenames=2,
uniquelist=false,
uniquename=false
]{biblatex}
\addbibresource{\jobname.bib}%refs.bib} %Imports bibliography file
\begin{document}
\section{Introduction}
\textcite{rvsheppard}
textcite: \textcite{rvsheppard2}; autocite\autocite{rvsheppard2}; and fullcite:\fullcite{rvsheppard2}; citetitle: \citetitle{rvsheppard2}.
\textcite{rvsheppard3}
\textcite{av} and \textcite{zz}
\printbibliography
\end{document}
Result:

Edit:
Had an idea overnight.
Here's another way, without changing styles or deep coding: just put the entire case reference in the title field, and use \emph{} or \mkbibemph{} to remove the italics.
It makes \textcite{} functionally useless, though, in terms of results.
@book{rvsheppard2,
title = {R v Sheppard and Whittle-v2\emph{[2010] EWCA Crim 65}},
}
@book{rvsheppard3,
title = {R v Sheppard and Whittle-v3\mkbibemph{[2010] EWCA Crim 65}},
MWE:
\RequirePackage{filecontents}
\begin{filecontents}{\jobname.bib}
@book{rvsheppard,
title = {R v Sheppard and Whittle-xxx},
date = {2010},
howpublished = {EWCA Crim 65}
}
@book{rvsheppard2,
title = {R v Sheppard and Whittle-v2\emph{[2010] EWCA Crim 65}},
}
@book{rvsheppard3,
title = {R v Sheppard and Whittle-v3\mkbibemph{[2010] EWCA Crim 65}},
}
\end{filecontents}
\documentclass{article}
\usepackage[
style=oxnotes-ibid,
firstinits,
backend=biber,
sorting=nyt,
natbib=true,
maxbibnames=99,
maxcitenames=2,
uniquelist=false,
uniquename=false
]{biblatex}
\addbibresource{\jobname.bib}%refs.bib} %Imports bibliography file
\begin{document}
\section{Introduction}
\textbackslash \texttt{Textcite}s: \begin{itemize}\item original entry: \textcite{rvsheppard}; \item with \textbackslash \texttt{emph}: \textcite{rvsheppard2}; \item and with \textbackslash \texttt{mkbibemph}: \textcite{rvsheppard3}.\end{itemize}
As can be seen with \textbackslash \texttt{textcite}, doubling-up occurs, since the same reference is in the text (as title) and also in the footnote (as reference).
\begin{itemize}
\item So, for inline use
\begin{itemize}
\item Use \textbackslash \texttt{fullcite}: \fullcite{rvsheppard3}
\item or \textbackslash \texttt{citetitle}: \citetitle{rvsheppard3}
\end{itemize}
\item And for footnote use
\begin{itemize}
\item Use \textbackslash \texttt{footcite}: some text\footcite{rvsheppard3}
\item or \textbackslash \texttt{autocite} if it is set to footnote mode: some text\autocite{rvsheppard3}
\end{itemize}
\end{itemize}.
\printbibliography
\end{document}
Result:

At some point, as the volume of references scales up, using a dedicated style/entrytype combination will be more efficient. And you may want to do other things too, like indexing and so on.
biblatex-oscolaif you are writing a law-heavy text. – moewe Nov 27 '17 at 17:47bibentrypackage is incompatible withbiblatexso you shouldn't be loading it. – Alan Munn Jun 01 '18 at 18:43.bibentry type for them. See e.g. Creating Entry in Bibtex for Executive Orders – Alan Munn Jun 01 '18 at 18:46@jurisdictionwould be the suitable choice here (despite the misleading name). At least, I think so. – cfr Jun 24 '18 at 13:32