Easy job - the panel it clips into is part of the dash under-panneling
Remove the 3 T20 screws holding the panel to the underside of the dash, (get your head in the foot fwell and look up - you'll see them on the edge of the panel) unclip the panel and it drops down and left. - remove the 12v socket clips - be careful as there isn't a great deal of slack on the cable to the 12v socket.
If you have footwell lighting, the stuff for that is attached to the panel too, so bear that in mind when removing ..