It starts easily enough with removing the batteries, to reveal 4 screws you can take out. That leaves it firmly stuck together at one end. What you have to do is,
Slide the silver cover on the back top down. A firm push on the raised semicircle should do it. Use a screwdriver to prise off the cover from the top, starting on the back where you have just exposed two small holes to lever in, and then on the front where you just have to work int in. Slide it up over the aerial.
Take out the final screw thus exposed, on the back near the aerial. The front now pulls off quite easily. Getting at the back however is more tricky. De-solder the tab connecting the aerial to the circuit board. Then the board should lift and pull out quite easily.
