I don't know if this will help but. . . .
When recorders are switched on they most likely select the AV1 channel to record from.
On the remote control for the Recorder there should be an "Input select" button.
Using this you can change the channel to be recorded from AV1 to AV2 or possibly a numbered Freeview channel.
I suggest you try a test recording from each different selection on the above remote control as you could be watching a different channel to what the recorder is tuned in to.