There are 2 torx screw caps that are on either side of the driving coloumn, they are semi-circle in shape at one end and have a little clip on them. Pop the covers off.
Use a (size 20? i think) torx screw to undo the screws.
Then in the top of the surround is another 2 torx screws. Undo these.
This will let you know have access to getting the speedo out.
UP and BEHIND the taco of the speedo there is a lever which clamps the wiring FROM the car TO the instrument cluster. Release this and its now un-hooked.
To get it out of the space it is in tilt the top of the cluster back slightly and push the right end into the unused space under the dash the pull the left hand side towards you and pull it our of the dash.
There ya go.
Install is reversal.