Will

  either father or mother will be the guardian to the minor children. and if you  distribute the property at 25% each parents can dispose the property by signing on behalf of the children.  so it is advisable that if you distribute the property at 25% each by a condition that the property allotted to minors should not be sold till they attain majority.  after they ( your grand children) attain majority, they (your g/c) may enjoy the property as they (Your g/c) wish.  This is for suggestion.

Thanks for reply. I thought the parents can't sign on behalf of minors and have to take court permission to sell the property. 

For any transaction  namely, alienation by sale or mortgage or any type of encumbrance on the  property standing on the name of minors, permission from the District court is essential and a mandatory criteria unless, such transaction will be considered as invalid in law.  So better to think about the next step of action to be taken, in my opinion, if your ultimate aim is that your grandchildren have to avail of the benefits, make a Will on your grandchildren directly and make their father as their guardian, why do you insist on selling of the property by your son or his wife intermittantly?

Thanks T. kalaiselan,

                                     Thanks for your answer. The property was bought by my son in my name. so technically, it is his property.  My son, his wife and 2 grandsons are all british citizen.

option 1- have all 4 names on will-

My son may sell the property only if he wants the money in UK (less likely) . I have no issues with it, even if he sells the property. But he will then have to go to court, if I am not around and his sons (my grandsons) are still minors ( say the year is 2020)

Option 2- On other hand, If I just put the name of my son and his wife (both British citizen) in the will, the property will be transferred in their name on my demise. Then they ( son and his wife)  may struggle to transfer the property to their sons( my grandsons) as all of them are British citizen. only advantage-  it will easy for them to sell the property (if needed). I don't know whether they can make  a will in UK and add a clause about the property in India. I believe it may not be simple as it will foreign nationals( my son and his wife) making a will in name of another foreign nationals ( my grandsons). 

In summary, I am just trying to find a solution which avoids trouble to my son and daughter in law  in future. I have no worries about their intention. I am just trying to think which option will be better and will cause less trouble to them. 

any guidance please