This issue was raised when the app was first released and the official response from Virgin Media at the time was that any device with a 7 inch display or smaller was classed as a phone and would get the phone version of the app. Only larger devices get the tablet version. I now have a tablet with an 8 inch display, but the same resolution as my old Nexus 7, and still get the phone version, so I think it's probably down to a combination of display size and resolution.
It would appear that nobody at Virgin Media or TiVo cares that the terrible user interface used in the phone version of the app looks even worse when scaled up on a tablet.
I think it maybe a combination of size and resolution but it should be upto the user to choose which version to install or to have a single version and options to switch the interface. The tablet interface is so much better than the phone version.
If you do what you've always done, you'll get what you've always got. Jim Elliot
I work for Virgin Media but respond here on an individual basis. No comment or assistance offered is done in any official capacity.