Un registered amendment deed of registered deed for Right to pass

In our civil suit for injunction against defendant ,we have sought court injunction for letting us construct our boundrywall behind a 10 feet passage as per our Registered family Agreement between parties where by the two parties having adjacent plot of land agreed to leave 5 feet each to form a 10 feet wide common passage for the parties & others. to which seller of the defendant was one member of the family.the agreement was dated 22/09/1980 contesting our suit defendant have produced an Unregistered Amendment deed dt.30/01/1988 showing that the actual passage is 12 feet wide hence the parties had agreed it to be 12 feet leaving 1feet each of there land. The amendment deed was never made by our family nor we had any knowledge of any such amendment neither there was any need to make any such amendment. On the other hand the defendant is bent upon to damage the existing sidewall constructions to force his claim and asking court for sight inspection and statous quo with a view to obtain legal stamp for his misdeed of illegal encroachment, We are advised to move sec 340.please advice whether such unregistered amendment agreement can be admissible in the court against an registered agreement. I shall be highly obliged for your expert advice.