Phew...ok
I had another look through X-CTU and it all looked ok - so I ran ATRE and put the commands in again on both devices and they seem to be working now - there must have been something wrong in one of the addresses I wasn't picking up on - (I'm not going to admit I put the Coordinators own address as the DL - and it didn't look that way but anything is possible!)
So yes both are now saying hello and I'm happy its going over the xbee and not through serial...now to play some more
Cheers chaps!