Sydney theme not adhering to .htaccess restrictions

Love your theme, but am having a problem with the theme not honoring the .htaccess restrictions I’ve placed.
I need this site to restrict traffic only to visits from a single, fixed IP address.
I have modified my .htaccess file to allow,deny from all
But when I visit the home page, the site still shows elements it should not.
Hosting support shows this to be an issue with the theme and not an error within the .htaccess file.
Can you please advise why the theme is not honoring the restrictions?

The site experiencing this issue is located here:

Hello there,

Not sure if the issue is with Sydney. To verify, please temporarily switch to the default WordPress themes like Twenty Seventeen.