Hi David,
It's best to move trees when they are in a dormant stage in the autumn, this month and next month should be ideal but make sure there is no frost forcast when you do it.
Prepair the planting hole well, take a guess at the size of the hole ( too big is better than too small !) this will minimise the time the tree is out of the ground. Fork over the bottom of the hole to help the roots get a good start, mixing some compost in to improve the soil is also a good idea.
Try to dig out the tree with a big a root ball as possible trim off any damaged roots cleanly then test it for size in the new hole and adjust if neccesary and plant at the same depth as before.
Back fill and firm it down as you go, making sure there are no air pockets and finally keep it well watered.
Ps it may need staking, if so knock it in at an angle of 45 degrees with the point, pointing in the same direction as the prevailing wind. use a good tie that will hold the tree away from the stake to avoid rubbing. Good Luck. Tbird+