Your digibox has digital tuners, your VCR has analogue tuners which complicates matters.
When your VCR was hooked up to the old tv, it used its own analogue tuner to record programmes. Now it is a bit more a faff to record, but not impossible.
You will need to set the recording manually - the channel will have to be AV1, AV2, EXT1 or EXT2 depending on how your equipment is connected.
Your digibox will have to be switched on to the channel you want to record for the whole duration of the recording.
An easy way to see which 'channel' to record:
1. Switch your tv and digibox on to a freeview channel not available to analogue.
2. Switch your VCR on and set your tv to view the video output.
3. Press channel 0 on your VCR remote, and use the down arrows which should go through the AV and EXT connections.
When you get the freeview picture, you will know which 'channel' the digibox is using.