[WPMU DEV Dashboard] Help with WP Job Manager

Hi

I'm trying to set up digitalscot.net as a jobs portal, and am using WP Jobs Manager and 'Capstone' theme to achieve this.

One particular weakness is the Salary field is hardcoded with a drop down list of options, in USD.

The theme author says I can use some code to modify this

(https://gist.github.com/imfaisalkh/5a908f74e9cadcdfb4ff8d6b14ff441e)

I'm not keen on hacking code just to modify such a simple setting, so am wondering what other options I might have?

I am trying this plugin: https://wordpress.org/support/plugin/wpjm-extra-fields/

but it's giving me an error, saying WP Jobs Manager needs to be installed for it to work, when it already is.

Any ideas on how to fix this, or other better solutions I might adopt to achieve this goal?

Thanks, Neil.