As mentioned previously, I am not going to build a "bundled" installer for 2.3.1. Indeed, I have removed the 'bundle' code from the installer at 8c32a1a7 and removed the bundled installer for 2.3.0 from the downloads page. I've added language instructing people to install a TeX distribution before installing LyX (as we do for OSX).
I have also written this wiki page https://wiki.lyx.org/Windows/TeXLive to help people install TeXLive and this page https://wiki.lyx.org/LaTeX/TeXLivePackages to help people learn how to install packages. I'd appreciate it if people could have a look and make whatever changes or additions seem worth making. We could probably use, on one of those two pages, a quick guide to updating the TeXLive packages using the GUI. Soon, I am going to write small batch file that people can use to install various packages that LyX might want. I'll link that off the wiki, and probably include it in the Windows installer. I mean just the file itself. Not running it as part of the installer. Riki