Extra space appearing before final punctuation in some footnote citations

Question

Apologies if this has been asked elsewhere; I haven't been able to find a question that addresses this issue exactly.

I am using Biblatex with the Oscola style and footnote citations. When I cite an @report style document, an additional small space appears before the final punctuation in the citation. This does not happen for other types of document. I'd like to get rid of the space if I can.

Here's an example. Footnote 1 is a @book - which isn't a problem. Footnote 2 is a @report with the awkward space. Footnote 3 has a problematic @report followed by an unproblematic @article.

Here's the MWE that produces that:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[style=oscola]{biblatex}
\addbibresource{main.bib}

\title{Footnote punctuation test}
\author{}
\date{August 2017}

\begin{document}

\maketitle

Here's a citation that works normally.\autocite{hajer_deliberative_2003} 
Here's one with an awkward 
space.\autocite{joint_committee_on_human_rights_human_2006}

Here are multiple citations (the first one shows the problem; the second is 
fine).\autocite{2014strategy,barrett_implementation_2004} 

\end{document}

And here's my .bib file:

@report{joint_committee_on_human_rights_human_2006,
title = {Human {{Trafficking}}, {{Twenty}}-Sixth {{Report}} of {{Session}} 
2005-6, {{Volume}} 1},
number = {HL Paper 245-I / HC 1127-I},
author = {{{Joint Committee on Human Rights}}},
date = {2006-10-13},
}

@report{2014strategy,
title = {Modern {{Slavery Strategy}}},
author = {{Home Office}},
date = {2014-11},
}

@book{hajer_deliberative_2003,
title = {Deliberative Policy Analysis: Understanding Governance in the Network Society},
shorttitle = {Deliberative Policy Analysis},
publisher = {Cambridge University Press},
editor = {Hajer, Maarten A. and Wagenaar, Hendrik},
date = {2003}
}

@article{barrett_implementation_2004,
title = {Implementation Studies: Time for a Revival? Personal Reflections on 20 Years of Implementation Studies},
volume = {82},
issn = {1467-9299},
doi = {10.1111/j.0033-3298.2004.00393.x},
shorttitle = {Implementation Studies},
pages = {249-262},
number = {2},
journaltitle = {Public Administration},
author = {Barrett, Susan M.},
date = {2004-06-01},
langid = {english},
}

Thanks in advance for your help.

Answer 1

As far as I can tell this problem was caused by a missing % in the definition of the macro report:standard. With

\renewbibmacro*{report:standard}{%
  \usebibmacro{author/editor/institution}%
  \setunit*{\addcomma\space}\newblock
  \usebibmacro{title}%
  \usebibmacro{reportinfo}%<--- % was missing here
  \newunit\newblock
  \usebibmacro{revisedbookvolume}%
  \newunit\newblock}%

there is no spurious space any more.

I have notified the author by submitting a pull request with the necessary changes to the GitHub repository: https://github.com/PaulStanley/oscola-biblatex/pull/6