My xbox power brick only turns orange, And wont turn on.

You'll need to order a replacement power supply at devicesupport.microsoft.com .

First, if you haven't already, register your console. Then you should be able to select it and then go to "replace an accessory" where you'll be able to order a replacement PSU.

I've noticed my X1 won't go into "instant on" mode after playing minecraft, after playing I turn the console off and it turn's fully off (orange light on the power brick). It also wont turn back on with the controller.

You could try, but I don't believe it's the power brick that's the issue. When the console is turned on, the power brick should be green. When the console is turned off the power brick should display an orange color. If it was flashing orange, red, or no
light then there would be a problem.

Had the same issue, turn console off and go away, when i return console wont turn back on (instant on), light on power brick is orange, unplug kettle lead from power brick for 10 seconds plug it back in and everything works fine.

I've only had this happen since i enabled the fast resume beta option for games, not sure if this is the cause tho.

Another way to fix the issue is to hold down the power button on your Xbox One for a few minutes, until the power brick turns orange, and then turning it back on.