F5 rarely forces a cache refresh I'm afraid (unless the content has expired - see below). It just reloads the page.

I think sometimes CTRL+F5 will do the job but I wouldn't rely on this.

Eventually the content in the cache will expire and then a visit to the page or a press of F5 will trigger it to be loaded from the server.

Just to confuse matters, some web servers also cache data! IIS used to have a very annoying habit of caching SWF files.

You can control the expiry of the index page using metadata but I'm not sure this would affect any assets loaded into the page.

An .htaccess file might be better: https://www.inmotionhosting.com/support/website/htaccess/apache-module-mod-expires