can you transplant a mature tree

Mature specimens require preparation a year in advance. During November to February, while plants are dormant dig a circular trench one spit wide parallel with the branch spread. Back fill the trench with sharp sand to encourage fibrous, feeding root growth which will help the plant to re-establish quickly.

Additionally, prune out approximately one-third of the plant’s wood.

Site preparation
Mark out the expected root spread plus an extra 50cm (20in) and dig the area to 30cm (12in) depth. Fork over the bottom of the hole, adding some organic matter.

http://www.rhs.org.uk/advice/profiles1000/moving_plants.asp

(Copy address and paste www bar at top of webpage bar! cant think of it name!)

Is better detail and more info

It sounds complicated...but its the best way...

Definitely if its established and a large tree, The bigger the root ball the better to! Although moving it may not be so easy!