Straightfoward stuff. If you’re waiting at a roundabout and traffic is coming from your right with no signal, they are going straight on - in other words, straight across you. So moving out would be daft.
If they then turn off prematurely, that’s not your fault and nothing would be marked on a test. But pull out on someone and you’ll be booking another test.
For the other fault, simply make sure you keep well away from the kerb on the approach and run it forward before steering left. Then steer towards the bollards on the exit road and keep it held out. Otherwise the trailer will be making friends with the kerb.
Hope this helps, Pete 