I click one 50m grid cross with the tape measure thing, click on the other, hit enter, type in “50m”, the dialog box comes up asking if I want to scale the mode, I click yes, the dimension tool line goes to 50m length and the model stays small. I must have missed out a step but what?
Notice that the dialog box also tells you that imported components won’t get scaled. Open the component for editing and then resize it.