You need to connect to the TV via a scart (I'll assume you've done this already to be able to watch them)
Your Video or DVD recorder needs to record from the AV socket to which the freeview box is connected, and NOT a channel number.
To try it, select a Freeview channel and watch it on TV. Then swith the TV to the channel you watch video's on. then select the channel (AV) on your video. You should now be seeing what is on your Freeview box, and from that you can record. If you see nothing, try a channel search on your video to see what it picks up.