IIS 404 error where file exists
Facepalm
New VPS box, means default behaviour. i.e. "Hide file type extensions for known types". When I turned that off, I discovered my file was actually named index.html.txt. Renamed it to index.html and problem solved.
Make sure "Common HTTP Features" under Web Server are installed. You can use Server Manager -> Roles -> Web Server -> Role Services to check, and install if it is not.