How big is the tree?
Whenw e took over our second plot there was a fairly mature dwarf tree, say 2m high, growing at a 45deg angle. We dug it up, with as much rootball as possible.. took three of us... and replanted it (in a different spot) upright, with support posts driven in at an angle so the top end faced into the prevailing wind, and the tree firmyl tied with cloth strips in a figure of 8 to protect the bark but render the rootball immovable. Lots of water for the first year, took off any apples for the past two Summers and now it is just fine and looks lovely. Stakes are staying in place of course
There is just about time left to be able to do this kind of thing, before the leaves come out, or leave it until the Autumn
Just another thought