In the track editor section, use the track property to select and set up the marker. Then, scroll down and write in the left menù the name of the station and which marker you need to use
Downloaded data from Defra Survey a moment ago, but I couldn´t download the whole area I wanted. Is it possible to go back and complete it later and sort of stitch it together with the previous batch?
Yes it is possible, I have done the LIDAR data for a 100 mile route in 4 stages. Just need to ensure you follow the steps to convert it with the exact same parameters.