To change the text alignment of the Brand Slider header from the default left position is very straightforward. 

You simply change the inline style of the header text that you have in the Slider Header input box. Sound confusing? 

For example: You change the original text below 

<h4>Our Favourite Brands</h4> 

To the following 

<h4 style='text-align: center;'>Our Favourite Brands</h4> 

Make sure you use single quotes as opposed to double quotes to enclose the style text. This way you can pretty much style the header however you want it using standard HTML syntax