When she passes, are you likely to be the only beneficary? Thinking out loud, so this maybe somewhat flawed. If so, then maybe she sells, and buys another property like you suggested with a Granny Flat. She lives in the flat, you in the house. You pay her 'board' to live in the house (equal to what you would pay if you had bought it). This would then give her a little bit of extra income.
This would mean the asset would stay in her name, so that she would not be "deemed' to be earning a certain percentage from the proceeds of the sale. When she passes, the property would pass to you.
This would mean the asset would stay in her name, so that she would not be "deemed' to be earning a certain percentage from the proceeds of the sale. When she passes, the property would pass to you.