update - Header image no longer visible

I’ve been away for a while so only getting to this now. A couple of issues have arisen since the Shapely update. I was using a plugin “WP Header image” to get specific header images on individual pages (plugin accessible on dashboard under settings). Since the update the header images are no longer visible and neither can I use the normal customizer header image to insert a generic header image. If you can solve either of these issues so that I can input some sort of header image I would be very grateful.
Thank you - the site is www.guided-mountain-walks.com

Hello there,

I hope you are doing well today.

The issue could be because of using an old cache in WordPress. Please try clearing your WordPress cache with the following plugin:

Also, please ensure that you have installed all pending updates available.

Best Regards,

Thanks for that.
I already have W3-total-cache plugin activated. Can I still install WP Super Cache – WordPress plugin | WordPress.org or are the two plug-ins incompatible?