I wanted to share my poor experience with Heart Internet in case anyone else is considering using them. I would advise against it.
My site was down for over a week with the dreaded message: Site offline The site is not currently available due to technical problems. Please try again later. . . which I could not understand as suddenly out of the blue I received that message. I checked and rechecked settings.php but saw no problem as I hadn't changed the file or the database, password, etc. Heart was duly contacted and denied any problems at their end.
I spent yesterday reading through 60 of the 125 results from a search for that error message. There seemed to be two main problems: either basic problem with the database name/password OR problem at the host with full disk(s), mysql server name change, apache needing restarting, etc, etc (things I had no control over). I sent that info to Heart and they said:
1. it was a PHP memory problem
(my php memory was 256M in .htaccess and php5.ini which I had prev set after memory probs so it definitely wasn't that unless on their side they didn't allow customers to set those AND none of the entries here that I read mention memory as a cause of this. I've had memory probs before and received different error messages)
2. they edited my php5.ini file