I think you should look into this a little more. There are a number of ways in which the transfer can be effected- the first is whereby you and your wife buy your sister in laws share- in this way you will get neither the FTB relief or consanguinity relief. The second is that your wife buys your sister-in-laws share- in this way, she will get consanguinity relief- i.e stamp duty will be halved because of the blood relation. But if you need to raise a mortgage to do so, the financial institution may require both of your names to be on the title if you do not qualify for the mortgage based solely on your wifes salary or income- NOTE some banks will allow the title to be in one persons name, and the mortgage to be in joint names, so check with your bank. Finally, you could buy your sister in laws half share in your name- you should qualify for FTB relief, your wife already owns the other half so this seems the best option.