If you happen to have Jetpack installed, it contains a ‘Widget Visibility’ module that is just for that purpose. There’s probably stand-alone plugins that do the same thing, though I haven’t looked.
Here’s a stand-alone plugin in case you don’t have jetpack installed: https://wordpress.org/plugins/conditional-widgets/
Many thanks for your help, guys.
You’re welcome. Hope you found something that works for you. Please mark this resolved if you think it is.