Caution there @Mavic-Max ... It's not measuring height from the controller - but from it's take off point i.e. where it is sitting on the ground when you press the start button. GPS location will take place, as well as barometric measurement to set a 'zero altitude' ... That's why it's a good idea to leave the Mavic on the ground'till you hear the controller message about your GPS position being updated - then do your take-off.
Thanks FoxhallGH I’ll bear that in mind tomorrow when I give it a go.