Silly mistake on my part! I hadn't initialized the correct CS pin of SD card to the Master Uno 
So now they seem to work in tandem with each other.
But the problem remains that even though I'm getting the necessary commands from the Master Uno to print on the Hyper terminal of the Slave, my LEDs on the Slave are just not glowing 
Further, I plan to replace the LEDs with up to 6 DC motors and therefore I need the SPI communication to happen perfectly and the GPIO pins to work (on the Slave).
Any suggestions on that? I'm really stuck in a rut here with this 