Shameless plug: You could install my
epubcheck plugin, which will also check the validity of .svg files.
For example, it reported the following error for your test file:
Code:
image001.svg 36 Fatal Error while parsing file 'The element type "g" must be terminated by the matching end-tag "</g>".'.
If you don't like the plugin or can't get it to work, you could also use
pagina EPUB-Checker, which comes with a nice GUI.