Readmore is text rather than button.

Hi

Using t3_bs3_blank template in Joomla 3.4.3

The Read More is just a text link and not a button. There in no mention of btn or class in the html so I can't write any relevant css to make it into a button.

Ideally I would like to use the bootstrap 3 code to make a button.

I have found the file below and tried changing it but it has no effect.
/public_html/layouts/joomla/content/readmore.php

Where is the correct file?

Thank you

John