Non alienation clause in the lease cum sale deed and its violation

A property was allotted by BDA, to an allotte and a Lease cum Sale Agreement was entered in the year 1996 Nov and possession was also handed over. There is a Non-alienation Clause for a period of 10 years in the deed. In the year 2002 Feb, BDA executes a ABSOLUTE SALE DEED, in favour of the Allotee. In the sale deed only a reference of Lease cum Sale Deed is mentioned and not a word about non-alienation clasue. Allotte in Dec.2002 (i.e. after completion of only 6 years only) to sells the property to a third party and thereafer BDA has also issued a KHATHA. Now the question is, 1. Is selling the property within a Non-alienation period amounts to violation and there by Sale becomes null and void ? 2. Does Absolute Sale Deed, superceds Lease Cum Sale Agreement, giving absolute power to allotee to deal with the property ? can someone throw light on this.