Yep, I’m sorry I should have mentioned that I had already found that line and changed it to my desired value:
$title = __( ‘Navigation’ );
The effect which this had was to change the page heading title on the Widgets management page. The “Widgets” entry on the administration navigation panel (under the “Appearance” section) remains unchanged…
I temporarily suspected a bizarre caching isssue but I have confirmed that this is not the case.
It’s a little confusing. Does changing this lines value for you have the desired effect?
Thanks for your continued help on this.