CGT payable by non resident on property acquired at different dates

In 2004 I was gifted a quarter of my father's house as were my two siblings. My father retained a quarter. My father died last month and his quarter share was given to me and my siblings so that we now own one third each of the house. When we eventually sell the house do I have to submit two Non Resident CGT forms? One for the 3/12 acquired in 2004 and using the 2015 value. The other for the 1/12 inherited at the time of death and using the value at the time of death. OR do I add the value at date of death to the 2015 value and treat it as one disposal?