As has been stated, the digital tuner is in the TV, not in the VCR. You can't tune your VCR to receive the channels directly.
You need a Scart lead connected from your TV to your VCR. (If either or both of these devices have separate Scart sockets for input and output, you need TV 'Out' to VCR 'In').
Your VCR should not be set to record a 'numbered channel'. Instead, there should be a button on the handset which permits you to select 'AV'. It's this AV 'channel' which must be selected to enable recording from the signal received through the Scart lead. True channel selection is done from your TV.
For example, to record 'Lovejoy', from ITV3 this evening, you'll need to have your TV receiving Channel 10 (ITV3) and then set your VCR to record 'AV' between 1855 to 2000.
If you're going out (so you won't be around to change channels) and want to record Lovejoy from ITV3 and also 'Death of a Nation' from More4, you can only do this if your TV has a timer facility which allows you to pre-programme channel changes. (Most digiboxes offer this facility. Many integrated TVs don't). If so, you'll need to set your VCR to record AV between 1855 and 2000 and also between 2100 and 2200. You'll then need to programme your TV to switch channels, from channel 10 (ITV3) to channel 13 (More4) at some point between 2000 and 2100.
Note that, because you've only got the one digital tuner (in your TV set), you can't watch one digital channel while recording another.
Chris