Changing width of single page

Hi there, i’m trying to change the width of a single page on my blog. It is here….

https://www.insertcleverrunningpunhere.com/races/

The tablepress table at the top is the table i would like to be wider. I can’t get it to expand any further to the right.

The table underneath is my older version, which clearly does run wider.

Why is this? Any ideas? Thanks in advance.