Question
I have a 40ft holly tree i need to remove.i would rather transplant than cut down. what is best time of year and soil type

Answer
The best time would be before the spring new growth starts. This is going to be a big job. Here is the US we have a piece of equipment called a Vermeer tree spade that can be used to move large trees. I do not know if there are dealers in the UK. Here is their web site in case. http://www.vermeer.com/vcom/EnvironmentalEquipment/Line.jsp?PrdlnID=3840

Here is also a site in the UK
http://www.vermeeruk.co.uk/default.asp?contentID=595


Deciduous  trees and shrubs may be planted either in the spring or the fall. Deciduous plants may be moved in the spring as soon as the frost is out of the ground, up until the time when new foliage is partly unfurled. In the fall, they may be planted once the leaves start to turn color up until the ground freezes.

When you want to dig up a tree or shrub for transplanting, retain as much of the root system as possible. Older deciduous trees  can be successfully moved only if a ball of soil is left around the roots. The exposed roots should be protected with moist burlap or newspaper or with polyethylene sheeting. Every effort should be made to reduce root exposure to wind and sun, keeping the ball as moist as possible. It's best to prepare the hole before digging up the tree you wish to move.

Size of the root ball and size of the hole:

For deciduous trees and shrubs the soil ball should be:

Width = 9-12 in. in diameter/every 1 in. of tree diameter
Depth = 6 in./every 1 in. of tree diameter

For example: A tree trunk 2 inches wide would need a soil ball of 18-24 inches wide and 12 inches deep.

Dig the new hole twice the size of the rootball and as deep. Fill with good top soil or potting soil and mulch around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk.