Leading (in paragraph settings) should default to 120% rather than 103% - like in other design software.
Apart from 120% being the standard in other software like Adobe CS. 120% leading is known to be best practice in graphics design in general. It's just a better starting point that does not even have to be changed in most cases.
Moreover a leading value of 120% has even been the default in the successors of Affinity products.
If you don't want to change the default of 103%, please make the default leading value configurable in the settings dialog!