I managed to find some logs by searching the entire hard drive for recently created files. Turns out, the log was at C:\Users\<username>\AppData\Local\Temp\SqlSetup.log. Details in the log are:

08/02/2012 06:54:45.744 Required version of Windows Installer is already installed

08/02/2012 06:54:45.746 .Net version 3.5 is already installed.

08/02/2012 06:54:45.747 Windows Installer version 4.5 is already installed.

08/02/2012 06:54:45.748 Patch related actions cannot be run from the local setup.exe, so continuing to run setup.exe from media.

08/02/2012 06:54:45.749 Attempt to initialize SQL setup code group

08/02/2012 06:54:45.751 Attempting to determine security.config file path

08/02/2012 06:54:45.763 Checking to see if policy file exists

08/02/2012 06:54:45.764 .Net security policy file does exist

08/02/2012 06:54:45.766 Attempting to load .Net security policy file

08/02/2012 06:54:45.772 Error: Cannot load .Net security policy file

08/02/2012 06:54:45.774 Error: InitializeSqlSetupCodeGroupCore(64bit) failed

08/02/2012 06:54:45.777 Error: InitializeSqlSetupCodeGroup failed: 0x80004005

08/02/2012 06:54:45.779 Setup closed with exit code: 0x80004005

The line at 06:54:45.748 seems somewhat strange. At least I have an error message I can research now.

Shaun