I would like to change the product details tab section to have a border around it, any advice on this would be great.
You need to changes on below file,
Basically this is coming from _sections.less file , but as per magento 's standard directly we don't need to edit that core file.
So override this _section.less in your custom theme :
That will help you for the same !
if u have that file, if not copy one from parent theme (probably Magento Blank) and edit line