As far as I know, this should not happen.
It can happen, though, if you have a HTML invalid page. That will cause the head tag to close early, and in some situations, can cause the browser to display whitespace where it shouldn't.
I found multiple errors trying to validate your site (see the w3 validator). The error that is most likely to be responsible for this behaviour, is that your head segment contains two different <title> tags:
<title>Rocksters Live Party & Wedding Band For Hire </title>
<title>Rocksters Live Party Wedding Band For All Events</title>
Note that this plugin only puts the things you give it into the head section, nothing else (no HTML comments or things like that). So if you don't add whitespace, it won't be displayed.
As far as I know, this issue is not directly related to my plugin. My plugin only inserts what you give it, so any issues involving the layout of a site, are probably related to what you are adding in the head segment.