I've successfully used park assist on my previous 3 vehicles and have found the E Pace park assist to be very good. It's a matter of confidence in yourself and belief in the function, don't get me wrong there have been a couple of times when I've thought oh no this is going to hit this and stopped but overall it's been pretty good. My advice would be to play about in a quiet street and get your distances from a parked car correct. Don't get too close but too far away and if will not pick up the parked car, I've found 3 ' to be a good distance for both parallel and perpindicular. If your having problems check that the sensors are clean as this can throw the system out. It can be a bit offputting when all the parking sensors start to go off but just do what the car tells you to do on the dashboard. Hope this helps.
I've never had this functionality before so went to a quiet street in town with lots on on street parking and tried it out. It found a parking gap between two cars I would probably not have chosen myself. I just followed the instructions and it worked really well. I am super impressed! I did wonder if the perpendicular parking was going to work because I couldn't quite grasp the logic of its moves but I followed it through (did as I was told by the computer) and it worked perfectly. I don't think it's likely I will use the perpendicular parking as it's easier to do it manually, but on auto street parking I will use.
I used the parallel parking mode just a few weeks ago and it operated perfectly.
Andrewindevon is correct, one has to select the mode first and then drive past the car that will eventually be behind you and then quite a way alongside the car that will be in front of you. The prompts seem quite accurate and just use the brake and throttle very gently. I kept about 0.5 to 1.0 metre away from the cars as i passed.
I need a lot more courage to perpendicular park but will have a go soon, when it's very quiet
I have the saame system in my Citroen currently. It works well but just be aware that it's only as good as the cars parking it is matching. I.e watch your alloys if the cars are parked close to the kerb!!!