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.
Update: this simple fix stopped working (or perhaps never worked in the first place) and I recently noticed my bare domain was no longer redirecting. Back to Google admin and I followed the instructions to add new A records to the DNS config in Netregistry (specifically, I added four new A records—one for each IP address noted by Google).
The Netregistry UI is awful for this task: Google suggests using @ for the name value but using @ or “.” or anything else in Netregistry didn’t work for me; I ended up leaving the Name field blank and setting only the Host field as the IP address. This created a new record with a “Record name” of mediawhole.com.