John, I probably assumed that will just wanted to plug something into the mains sockets in his van like a hoover or lamp or mains tv. The mains supply to the van goes into the power unit and through fuses then either to the 230v sockets or the charger. So the 230v sockets can be used independantly of the 12v supply. They are seperate circuits.
You should have a battery in place if you are using the 12v supply in the van via the charger unit and as John said direct feed through the transformer without a battery in place could damage a tv running off 12v.
Sorry for any confusion.