Classifieds Single Template in my Child Theme showing an error

Hi Support

I would like to change the output of the cost field to auto include a currency symbol. I get the following error on a single classified page.

Using $this when not in object context

What I did was to copy the classifieds\ui-front\general\single-classifieds.php from the plugin and move it into the root of my child theme. (the parent theme is canvas from WooThemes)

I check the usage tab on the classified directory page on the site and you dont mention anything about being able to overwrite the templates.

Can I overwrite the templates like this or should I be using a filter to modify the output. Am I missing something that should be included?