1. No probate of the will has been availed by the beneficiaries after the death of your father,
2. Without probate, a will has no value more than a scrap paper,
3. The unregistered settlement deed also has no legal value till it bis registered, before or after 12 years of its execution,
4. You can refuse to register it now and file an application seeking the grant of probate of your father's will,
5. After that you can file a partition suit claiming your share of the property as per the will of your father, application for probate of which has already been filed by you.