If you do entry tests before hand, they would hold a heavy weight on their decision to give you an interview. But if you have good UCAS points and good predicted grades, you are very unlikely to get rejected before interview. It is a whole different board game then, you just need to impress at the interview stage (or just not look too too thick-which they will make you feel, without doubt).
In order of importance, I would say Entry tests-UCAS points-Predicted grades... then the deciding factor is the interview. But note that that predicted grades are mainly a consequence of the UCAS points, and you have to take them with a pinch of salt, whereas UCAS points actually show what you have achieved