Company purchase

One of our clients is a company, largely owned by trusts, it is predominantly a property investment company, but it also owns approximately 20% of the family group holding company.
The family now want to change the structure and bring the property investment company into the group buy buying all the shares. If this happens what happens to the 20% holding in itself - presumably the shares have to be cancelled? Do the company have to apply to the court for permission to buy it's own shares in this case?
Richard Spencer