Capital gains tax on house sale when grandparents have been part owner-occupiers

Hi, I would like to know how CGT should be calculated for a potential house sale that I have part owned with my grandparents who have recently passed away. The home in question was originally bought from the social rental market in 2008, (total value approx £30k at the time) and my grandparents, who ultimately wanted the home to pass to me on their death, put the home in equal 3 way ownership between me, my grandad and grandma. In 2017, my grandad passed away and left his third of the house to me in his will (total house value at the time approx £120k), and my grandma continued to live there. In 2021, my grandma gifted her remaining third of ownership to me (total house value at the time approx £150k). She then continued to live there rent free until she recently passed away. I now need to decide what to do with the house, to rent or sell (approx value now £160k) How would CGT be calculated in this scenario?

Hi,
You will take 1/3 share when in 2008, another 1/3 share of the value in 2017 when your grandad passed and then the final 1/3 of the vaue in 2021. all added together this is your purchase price for working out any gain.
Thank you.