I don't know why Microsoft made multiple versions of Visio and Project. I have Project 2010 Professional and Visio 2010 Premium, but I not tried Project Standard, Visio Standard and Visio Professional, so I don't know what is difference. Also, when you install Visio 2010 (Standard, Professional or Premium), it says in installation that you are installing exact version of Visio 2010 (ex. Installing Visio 2010 Premium). For your problem, uninstall Visio 2010 Premium and install Visio 2010 Standard.
Thanks for the reply, you're right, that's what I should really do, but the ospp.vbs script does actually work, I was just hoping someone would know a bit more bout how Visio knows what Version (Premium, Professional or Standard) it now is, because it does report Standard correctly once the script has run, I just don't know how to read that programmatically.
200 copies? I'm guessing your not using this for personal use - in which case you really should buy it on some VL agreement. Your company are taking a huge risk operating with pirated software on this scale.
It is on a VL agreement, but Premium costs more than Standard on the agreement that's why I have to get all of them to be Standard having installed the wrong version by mistake.