https://www.agi.org.uk/wp-content/uploads/2020/11/BS7666Guid...
4.4.1 Street names The designated street name is usually to be found on the name plate on the street. However, these may not always be correct, and may differ between the ends of the street. Unofficial street names are ones that have not been adopted by the appropriate Highways Authority but may be in common usage, e.g. "The Great North Road". Street names, whether designated or unofficial, should be recorded in full. Abbreviations and punctuation should not be used unless they appear in the designated name, e.g. "Dr Newton's Way". Only single spaces should be used.
So I think all its saying gazetteer editors should not add punctuation if its “missing” from the designated place name.
Punctuation is fine if it already part of the place name.
I think the intention is to preserve the original place name.
So the council is wrong to blame the specification.