Regardless? Really? Even if the way the family acquired the land was also "pure theft"? At bottom it's conquest + inheritance for nobility. IOW, pure luck. I think it appropriate that government redistribute such land someway.
Ditto for the various religious organizations too. Henry VIII took much land and wealth from the Roman Catholic Church.
If I remember right, that family received it as a gift from a king at the time. While in principle I agree with your notion, I don’t think the government should be taking away property in this day and age anymore.
At the end of the day, how far do you have to go back to protect property rights? If a family has owned a plot of land for nearly a thousand years, is it not yours then? Do we need to go back further?
Regardless of how they acquired that land in the first place, that's pure theft. And I've also heard several stories of how they lost significant wealth due to shady characters.