How hard is it to get into Sussex University by clearing?

If I miss my grades to get into Durham, I want to go to Sussex uni since it is local and I can live at home. It is the only university that I want to go to through clearing because of this. For this reason, I am concerned that I will be unable to get through to them on results day since I don’t know how busy the lines will be. Has anyone gotten into Sussex by clearing and what was your experience of it? Will they look unkindly on me wanting to study Neuroscience rather than Biological Sciences, which is what my firm offer is for? Thanks