After 2 downloads for FMP Advanced returning me with plain vanilla FMP 12 I trashed the dmg files and the resulting fmp 12 trial applications and sent Filemaker an email telling them my attemp to download FMP 12 Advanced resulted in the download of FMP 12 not FMP Advanced.
Their reply suprised me. They said :
"We do not offer a trial version of FileMaker Pro 12 Advanced. We only offer trial versions of FileMaker Pro 12 and FileMaker Server 12 Advanced. "
So, if you were thinking of trying before upgrading to FMP advanced don't waste your time.