1) Organisations also count as things.
2) The section you quote from WP:NAME is in the section titled "Use English words", which goes on to say "Sometimes the usual English version will differ somewhat from the local form as in Franz Josef Strauss; and rarely, as with Mount Everest, it will be completely different." This is clearly a case where the "usual English version" differs somewhat.
3) Wikipedia:Naming conventions (political parties) carries several exceptions: the third exception is "Parties whose name is more commonly known by acronyms than their full name in international newsmedia." Since GPV is more commonly known by its acronym, this naming convention does not apply.
4) There is no problem with ambiguity, since there are no other topics in Wikipedia that carry the name GPV.  Even if there were, this article would then be named GPV (political party) to disambiguate them.
In conclusion: please read naming conventions in full before quoting them to me.  Also, please demonstrate that GPV is not the most commonly used name in English for this party, which you have not yet done. Thank you.