Just tried to do the latest firmware update via mobile and it failed, I know I can do it on my pc but I don't have that luxury at the moment because I'm away from home but what's concerning is now the Drone won't switch off and the two middle LEDs are on solid, HELP!!!!!

I have the same problem.

For just now i follow and study this stream ...
http://forum.dji.com/thread-78006-1-1.html

This means that the battery upgrades failed and you need to upgrade the battery again. To fix this issue, upgrade the battery firmware again. Please remove the battery and try to charge it for about 2 hours, and then mount the battery to the aircraft, connect your drone to the computer and try to upgrade it via DJI Assistant 2 again. The middle 2 LED lights will keep lighting and the power button of the battery will not work until the upgrade is successful.

This happened to me yesterday and I had it fixed this way.

Turn on remote control and DJI Go App. Plug in the problem battery (with two middle  indicator lights on) . You will find the Mavic would turn itself on and do its routine reboot. On the DJI App, you will see a warning message saying something like "inconsistent firmware" (I forgot exact word). Select upgrade. It would start upgrading and soon the battery middle two lights would turn itself off and make sure you wait until the whole upgrading process is finished 100%, then you are good to go.

I hope this helps.