Is there a simple way of maintaining a left handside navigation bar without changing every single template. For instance just now if I wanted to change the colour of the navigation bar, I would have to go and edit every single template file that uses the Navigation bar.

Will this work:

See the way that it puts the header.txt in wherever it says <%%header%%> then will I be able to put a tag wherever I want my navigation bar like <%%navbar%%> and upload navbar.txt to the templates directory?

Thanks In Advance