Hi thanks for your comments,
You are correct in all your assumptions, I used a female micro HDMI to male mini hdmi converter to connect the video output of the MK802 (I could only find one seller on eBay in the uk selling these)
I liked the idea of having the MK802 standing up in the dock but the connectors were so close to each other and would not allow the MK802 to stand up on the HDMI socket with a micro USB adapter connected as well so I had to do a slight mod to the lapdock and move the micro USB connector inside the lapdock case, I could then connect a female micro USB socket (which I spliced from an old lead) and create a short lead which terminated in a full size USB plug that could be connected to the MK802's full size USB socket in order to hook up the keyboard, trackpad and hub.
At the time of the photo this USB lead was just hanging out of the bottom of the lapdock case but now it comes out of the hole where the micro USB used to be, you can see this in the video.
One thing that has to be done when connecting the MK802 to the lapdock's micro USB socket is to remove the red power wire that tries to send power from the lapdock back up the lead to the MK802, whilst you would think the MK802 could be powered from this, it can't, well it can but then USB won't work. I oringinally tried this using the mini usb connector on the MK802. The guys at Pi found this out and split the lead out and used the red power wire to power the computer.
At the moment I just power my MK802 from one of the USB sockets on the lapdock using a standard to mini USB lead.
The plan is to make it neater by using a right angled USB lead for the top of the Mk802 and then taking the power from the micro USB connector (now inside the lapdock) and have a small mini USB lead coming out of the same hole as the other USB lead which would connect to the mini connector on the MK802.
I'll try and put up some close up pics soon to make it a bit easier to see!
As for your question about battery life, it's pretty good actually. I got about 3-4 hours out of it and im not actually sure if the battery was fully charged. I thought that was pretty impressive.
All the best,