If you have a digibox, VHS and digital TV each with 2 scart sockets you can use this set up. However, the VHS must have an AV or EXT input and not just an analogue input. If it has scart sockets it should be OK.
Main ariel to digibox then to VHS then on to TV. One scart lead direct from digibox to TV. A second scart lead from digibox to VHS and another scart lead from VHS to TV.
Your neighbour can then choose to watch the digital TV with the other two switched off, or watch a digital channel via the digibox. If she wants to record a programme she would need to select the programme to record on the digibox and select the correct input on her VHS. It could be EXT2 or AV2 or similar, check instruction book.
Whilst this programme is recording she could watch a different digital channel using the TV tuner.
Switching on the digibox or VHS will usually overide what ever is on the TV at the time. She would have to switch back to the TV manually whilst something is being recorded.
Can't guarantee this will work for her but it works for me.