Second problem - second thread. Otherwise you'll miss the best answers.
Never use the space bar to position text.
In your header, before the page number field, press the Tab key twice.

If you think your styleref field will ever give you a string of text longer than half your margin-to-margin distance, modify your header style to delete the center tab and only use one tab key press. (There is a right-tab setting in your header style.)

Sections / Headers and Footers in Microsoft Word 2007-2010

Basic Formatting in Microsoft Word
Basic concepts of Microsoft Word: An introduction