I'm a bit confused!
First of all,it should be possible to record the Freeview signal on your DVD recorder without an extra digibox (although you wouldn't, of course, be able to watch a different channel at the same time). Secondly, you've not stated how many Scart sockets there are on each device.
To get everything to work properly, you need to get an RF signal to all 3 tuners (i.e. the 2 digital tuners in the digibox & TV, plus the analogue tuner in the DVD recorder). Although the digibox almost certainly has 'RF loopthrough', I doubt that the DVD recorder has. For this reason, I'd purchase an aerial splitter. (They're only about a quid). You might also need an extra aerial fly-lead. (Another quid or so).
Assuming that there are 2 Scart sockets on the DVD recorder, here's how I'd connect it all:
Aerial feeds into splitter.
One side of splitter feeds, via a fly-lead to TV. (This guarantees that your TV will receive an RF signal for its digital tuner to process).
Other side of splitter feeds to digibox.
Then connect another aerial flylead from the digibox to the DVD recorder. (This now means that all 3 devices have an RF input).
Now connect a Scart lead from the digibox output to the DVD recorder input. (This is necessary, as well as the aerial fly-lead, to transfer the decoded digital signal to the recorder. It's in AV format, not RF).
Lastly, connect another Scartlead from the DVD recorder output to the TV.
When recording signals from the digibox, on the DVD recorder, remember that the digibox needs to be set to the relevant channel (e.g. channel 10 for ITV3) but the DVD recorder needs to be set to record 'AV'.
Chris