The place for the contraband was on top of that deflector thingie at the rear of the bomb bay
I found out about that during one of the closing parties when the Valiants were scrapped. XD 214 inventory was in my name and the chief tech, whose name I will not disclose, in charge of the aircraft filled me in with the details.
It was obviously a favourite because all the hot and high takeoffs I did with that aeroplane would be on the nail at Acceleration Check Speed Speed and then use the last inch of calculated take off distance.