I eventually found the answer myself in Properties lost during Maven release:perform where the answer explained that there is a forked process for release so to get the command line property recognised and have it to override the property set in the POM must it be passed through as
-Darguments=-D...
and the command I must use then looks like this
mvn release:prepare && mvn release:perform -Darguments=-Dskip.deploy=false
Thanks to myself for answering this question and thanks Stephen Connolly that answered the other thread. It is just sad that I didn't find that answer until know in all the noise that come up when I try to google for it.