I thought the TiVo AUX SCART was input only - that its only purpose was to accept the signal from a Sky or Freeview STB. If that's right, then the connection between your TiVo and DVDR won't let you record to the DVDR from TiVo.
If I'm right (and I'm much less of an expert on TiVo cabling than many others here, so if someone disagrees with me you should probably believe them!), you need to use either the TV or VCR SCART on the TiVo to send stuff to the DVDR's input SCART. The TV SCART is preferable, because that uses the higher quality RGB signal rather than the muddier composite signal that the VCR SCART uses.
If you do use the TV-out SCART on TiVo to connect to the DVDR's input, to get RGB from TiVo onto your TV you will need to loop the signal through the DVDR onto the TV, which is what the suggestion I quoted in message 3 above was trying to say. This assumes that your DVDR supports RGB "loopthrough" (if that's the correct terminology - someone with better jargon will have to confirm it).
So, if your TV has two SCARTs, the daisy chaining would be as follows (You've not mentioned an STB for Freeview or Sky anywhere, so I'm assuming you don't have one).
RF from wall to TiVo RF-in
TiVo RF-out to DVDR RF-in (assuming you want to record off-air to DVDR)
DVDR RF-out to TV RF-in (this lets you watch live TV without going via TiVo)
(this arrangement for RF assumes your DVDR supports RF loopthrough. My understanding is that most do)
TiVo TV-out scart to DVDR input scart (this lets you record RGB quality from TiVo to DVDR)
DVDR output SCART to TV SCART 1 (which is almost certainly RGB. So, you watch DVD or TiVo on AV1)
VCR scart out to TV scart 2 (which might not be RGB, so use it for the VCR)
(This doesn't let you record to VCR from TiVo. If you want to do that you would need to connect the TiVo VCR scart out to your VCR's input scart. If your VCR has two scart sockets you could have both sets of cabling there together. If it only has one you'll either need to move the cables around when you want to do this, or you'll need to watch VHS by pushing the VCR button on the TiVo remote)
(Neither does this let you record off-air to VHS. I assume you don't want to do that.)
So, that gives you DVD and TiVo on AV1 and VHS on AV2. Depending how well behaved the SCART switching in your TV is, it will probably flip automatically between them when it detects signal on one or other - so, when you bang in a video it will flip to AV2, and when you put in a DVD or turn on TiVo it will flip to AV1. You'll need to find out by trial and error what your DVDR does if you are both playing a DVD and have TiVo turned on. My guess is that it will show the DVD unless you press a "monitor" or similar button on the DVDR's remote.
This arrangement lets you record off-air to the DVDR. It also lets you record from TiVo to the DVDR using TiVo's "Save to VCR" function.
In this arrangement your VCR is used only for playing (not recording) VHS tapes.
I'm no expert, so your mileage may vary. Value of DVDs can go down as well as up. Close cover before striking. Stay away from children and drink as much as possible.
