BDA Sale Deed

Dear Friends,

City Improvement Trust Board (presently Bangalore Development Authority) allotted a Site bearing No.72, measuring East to West 124 Feet and North to South 80 Feet, formed in Jayanagar III Block, Extension, Bangalore to one Mr.S.K.Raja after collecting entire site value of Rs.9,920 on 10/6/1957 and later issued Possession Certificate on 30/7/1957.  On the basis of this Mr.S.K.Raja sold the above said property in favour of Mr.G.N.Senkaranaraian by executing a Sale Deed on 21/11/1962. On the basis of the Sale Deed Mr.G.N.Senkaranaraian duly transferred Katha in his favour in the concerned Bangalore Mahanagara Palike. While during the Katha transfer at that time revenue department did not insisted for the production of valid BDA Sale Deed from Mr.G.N.Senkaranarain. Whereas Mr.S.K.Raja did not get the valid BDA Sale Deed in his name.  Mr.G.N.Senkaranaraian bequeathed the above said property by executing a Will in favour of his wife Smt.G.S.Susheelamma as life estate (life interest to use and enjoy) and after her demise to his 3 sons namely 1) G.S.Ramachandra Gupta, 2) G.S.Srinivasa Gupta and 3) G.S.Sathyanarayana Gupta as the beneficiaries after the death of the Testator and his wife. On the basis of this Will the three sons applied for Katha transfer in their names which is rejected by the BBMP for insisting them for production of valid BDA Sale Deed which is not their possession.  My question is why the revenue department did not insist Mr.G.N.Senkaranarain for production of valid BDA Sale Deed during the katha transfer at that time.  But after 42 years in their legal possession without a valid BDA Sale Deed, the revenue department insisting for production of valid BDA Sale Deed, where both the Vendor and Purchaser are demised. How to get valid BDA Sale Deed and in whose name to get the BDA Sale Deed for the valid Katha transfer.  Kindly advise.

Thanking You in advance,