We own a .co.uk address and use an Internet hosting company that has made mistakes around DNS in the past. Our main site is hosted on www. and their reluctance to allow editing of AAAA records on-line means our naked domain does not resolve.

Currently when we attempt to reach the naked version there is no entry for the browser to go to and it displays an unreachable page (nslookup just says Name: name of domain with no further entries such as an IP or Canonical Name).

We recently added the relevant TXT records to verify us to view both the www. version and the naked version of the domain in Google Webmaster Tools (in anticipation of the requests to our Internet host coming to fruition).

Imagine our shock when double checking the Site configuration > Crawler access and finding a (admittedly failing) robots.txt with a dynamically generated HTML page (full of crude pop-up JavaScript) with references to 3 of our most prominent competitors.

What could cause this to happen?

As we are in the UK I am assuming some DNS server is serving Google bad information. We are going to contact the Internet hosting company to fix our A and AAAA records once and for all, then check that they work in the US (using something like OpenDNS). Should we be doing more though, for instance informing Google (through Webmaster Tools) that we are now aware there is something currently wrong with our naked domain?

UPDATE:

We have fixed our A records (not AAAA) and that has resolved the issue. But if there are further actions we should take for effectively having a parking page hosted on our active visitor-heavy, SEO-rich domain that advertised our competitors to US visitors, what would they be?