I have inserted an iframe with a blog as the source. This is all fine however when I try and add text further down the page, it does not show when I preview in safari. When I click on live view the text shows fine, but it seems to have a problem when I preview in safari.
Put a visible border on assorted elements so you can easily see if they're where you thought they were.
You will have to explain the difference between "preview" and "live view" because this sounds application-specific. (For example when I say preview it means the text editor's built-in www preview, which uses webkit and is therefore almost identical to Safari, while "live" can mean either MAMP or, well, live.)