Theme files modified and uploaded via SFTP not running on live site.

I’ve recently inherited a Drupal site after our previous developer left. He didn’t keep exhaustive notes and is currently unreachable.

I’ve managed to get access via SFTP, and located, modified and re-uploaded the files that required changes. The files were page--front.html.twig and style.css. They both have clear and profound changes, that do not show on the live site.

Should these files show immediately following changes, or are there extra steps necessary?

P.S. I’m not aware of an external caching or CDN source and am not aware of a hard server cache associated with Drupal, so don’t think that’s an issue.

Drupal version: