I have created SVN host using:
<Location /svn>
DAV svn
SVNParentPath /home/xxx/xxx/xxx/xxx/Main_Folder/company-1
AuthType Basic
SVNListParentPath On
AuthName "Test"
<LimitExcept GET PROPFIND OPTIONS REPORT>
Require valid-user
</LimitExcept>
</Location>`
Although I have specified user privileges in svnserve.conf, it does not seem to "take it" because I can access the repository (see below) without any prompt for user/password.
Can you please point what am I doing wrong?
Thanks!

Read the docs, it seems that you use a wrong configuration file.
Configuration settings in the file
svnserve.confdo not have any effect in this particular case. Your server runs Apache and Apache does not processsvnserve.conf. This configuration file is used bysvnservecustom server only.