Possession Under Mandatory Rights Ground 1

Tenancy Deposits

My brother is a vicar and due to retire this year.
He rented out our family home which was left to him almost three years ago but for the last 6 months has has no rent . The tenants are now digging their heels in big style and they have moved their 25 year old unmarried daughter with ayoung baby into the property without permission.

We have served a legal Section 21 but HARP picked holes in it and said we had no basis with which to go to Court.

I always believed that under Ground One of the Mandatory Grounds , if it was the landlords only residence and they needed it to live in and it could be proved it was the family home , possession would be granted by the Courts.

The tenants were requested to quit on the 12th March 2009 or face possession proceedings when sent a letter giving two months notice to quit because my brother was moving into the property

Despite HARP picking holes in it, I think it was a legally served valid notice to quit served in accordance with their tenancy agreement and would like to go to Court after the 12th on the basis using Ground 1 for the reason for possession.

Any input from the forum would be appreciated.