Thanks to Dell EQl support for explaining this:  The version check for .NET 4.5 in the SAN HQ installer is buggy. The workaround is: - unpack the SANHQ installer exe (7-zip can do that) - there is a file  „.rsrc\FILE\40008“ which is the actual installer and about 65MB large - rename this file to something with .exe and installation execute to install SAN HQ - make sure .NET 4.5 or higher is installed (latest version available at time of this post seemed to work) 
I cant get 3.1 to install on 2012R2 because it tries unsuccessfully to install .NET 4.5 which is already installed. Is anyone having this problem and/or did you get past it?
SANHQ 3.1 Install Problems