you need to get the pre-load on the maxle's tension nut (on the disc side of the fork) correct
if its too loose there will be play, if its too tight there will be also play!
also make sure you have use the Maxle lever to drive the axle firm against its threaded stop (using the lever in the notch on the axle shoulder) as otherwise when you lock the Maxle lever over there will still be play
You were spot on - with a lot of playing about its now fine.
Feel like an idiot! Cheers all