You should be able to go to Saved > Recorded > See all > and click on the Recorded tab you will see a drop down with the following options:-
Recorded, Recorded on this Virgin TV box, Planned, and Planned for this Virgin TV box. - highlighting "Recorded on this Virgin TV box" will just show those programs recorded on that box.
There are also some pictures and video on this thread, see from message 4,
https://community.virginmedia.com/t5/Forum-Archive/New-boxes-and-I-can-record-to-both/m-p/4595521#M5...