CGT on sale of deceased's property partly owned by dependants

My wife's father died 10 years ago, leaving 40% of his home in his will to his 4 children, with his wife retaining the remaining 60%. She died 2 years ago, when the 60% passed to the same 4 children in her will. It is only now however that the property has been sold, so my question is, how should CGT be calculated? Rough idea of numbers and dates below: 2014: father dies, property valued at £400k, 40% inherited by children 2022: mother dies, market value of property £600k; balance 60% passes to children 2024: property sold for £530k So how do you calculate the CGT, and how do you enter this on the HMRC form, as it's essentially two different 'transactions' in terms of the children - a 40% share which they've owned since 2014, and a 60% share they inherited in 2022, on which they have suffered a loss when sold? Thank you

Hi,
You take each share of the value when the father died and also the share of the mothers value at time of death. Added together, this is your purchase price. The date acquired is the date the father died irrespective of the share. 
Thank you.