Is there an option to disable the ALT key so I can alter note pitches just using the up and down arrown - having to use the alt key plur the arrows is really inconvenient. 
IIRC that question has been asked and the answer has been negative.
If you can find the original thread, it lists the reasons why.
Perhaps there is a way to create a custom shortcut on your computer.
I don’t think there’s anything to stop you redefining the key commands for e.g. Note Editing > Lower Pitch by Step or Raise Pitch by Step in the Preferences dialog, but I would urge you to reconsider – we designed Dorico such that the arrow keys alone navigate and you have to add Alt to edit the music, as a deliberate tactic to try to avoid accidental editing.
I also wanted to mimic the behaviour of Sibelius at first, but quickly saw the benefits of the consistency in which navigating/moving items throughout Dorico works. I was surprised how soon I got used to the alt-key. 
Thanks guys, I will try and persevere for now and see how I get on.