XBee, XBee Shield and Audrino Leonardo - Communication problems

Hi, I am creating a project which requires communication between 2 XBee radios.

My setup is as follows:
2 x Arduino Leonardos
2 x XBee series2 (X24Z i believe)
2 x XBee shields

Anyway, I used X-CTU to configure one to a coordinator AT and another to an end point AT
coordinator - firmware v20A7
panid 2222
DH 13A200
DL 40992C53

end device firmware v2A87
panid 2222
SH 13A200
SL 40992C53

So I mount each XBee in the shield and connect this to the leonardo. Configure my jumpers to what i think is correct (what positions would people on here recommend). The XBee association lights start flashing at about 1Hz. The endpoint leonardo L LED (next to the TX and RX lights on the aurdino - i think it's pin 13) just freezes and the associate light on the sheild flashes very fast. The Arduino board then just locks up - I cannot reset it.

I have tried flashing both aurdino just to the blink sketch, but the same thing happens with end point XBee

The strange thing it this was all working fine on the weekend. I would just plug the XBees in, power up the board, then they would assoicate fine and I can run my program on the Arduino. I thought an XBee could of been broken, but I ordered a new sheild, XBee and arduino and the same problem is still happening. I am at a complete loss at understanding what is going on.