Resolved this. The description for the ISO downloads on the File and Formats page said they can be burned to disc, so I assumed each one was burned to its own disc. On the Download page, expanding the Additional Information and/or the Installation Instructions explains the steps to concatenate the files into a single ISO image that can be burned to disc. Rick  
Download the most recent SUU isos; burned the images to a DVDs; loaded DVD 1 in server; Selected the updates to perform; click on the Update button... Nothing happens.  Updates aren't performed. Is something wrong with the latest 2 disc set? TIA  Rick  
SUU Updates not being performed