It looks like you are doing some kind of URL masking. The URL in the browser displays “http://www.garyhobbs.co.uk” but it’s actually displaying content from another URL “http://essexrubbishremoval.co.uk”.
This is a little bit dangerous grounds. Displaying content in an iFrame from the same domain is different than displaying content from another domain. The pishing filter of the browser is obviously going to have issues with it. Imagine me setting up a site and displaying the content of “PayPal” site in it! I know you probably own both domains in your case but the browser doesn’t know that.
Anyway, the plugin does not have any restriction as to what you are doing but how the browser handles it is a different issue.