Something changed in relation to the root redirect I previously had in place and I only just realised (my domain host, Planetdomain, is now owned by Netregistry so I attributed it that change initially but I suspect Google may actually be at fault here). In any case, mediawhole.com was not redirecting automatically to www.mediawhole.com and was coming up with a 404 or something equally boring instead.
I thought I’d need to mess around with DNS records at Netregistry to fix this but in actuality it was a simple as typing “www” into a text box in the Domains section of the Google Apps admin console. Google refers to this as redirecting the naked domain and provide suitable instructions on the process. In my case I didn’t need to configure A records as they were already in place.
The root mediawhole.com domain redirects efficiently, automatically, and as you might expect.