So after about 15days wait, the Broadcom Crystal HD Mini E-PCI card showed up.
So after re-reading these two great posts I started to the "upgrade" of my Apple TV.
So got the card out ...
next it was time to take apart the Apple TV, Carefully pulling back the rubber base at each corner and using a torx headed screw driver undo the 4 screws in each corner.
This then allows you to break apart the apple TV, be careful of the harddrive cable, detach it and you then have much eaiser access to swap out the card.
Next take off the wires that go to the wireless card, I then taped the metal ends and secured them out of the was (shown below)
Place the plastic foot on the new Broadcom HD card, Fit the new card and re-screw in place.
Already to go back together.
ATVFlash patching setup I didn't have to do any scripting as it has been added to the extras menu.
So after installing the software, and doing a full power cycle I was able to chose the Broadcom HD as the decoder in the video setting of XBMC.... I was then able to watch a full 1080p mkv 6.5Gb moive streamed of a 100mb lan. Got to love XBMC :)