I need to change my bike from UK to US Spec
Kind of what Daniel said, brakes are easy. Sit down and think about it for a minute, all you have to do is switch the cables. Run the front cable to the left and run the rear cable to the right.

If you want to switch the shifters you will probably run into some trouble. You won't be able to just switch the cables, you would have to get shifters that work on the opposite side. I would just forego that goal if I were you.