Public chargers can be finicky to get to start for sure, but in my case I had problems that turned out to be because I'd set the car to schedule charge (in the infotainment settings in the car), but in the app I didn't have schedule charge set. With this set up I had to confirm the charge in the MG app before it would start charging, which required my PIN to be entered, and often this failed the first time and the charger software would time out while I was faffing around. Since turning off schedule charge in the car's settings, I have had fewer problems - I just plug it in and it gets started pretty much straight away mostly.
I don't have a dual rate tariff etc, so I don't ever schedule charge, but when I first got the car I'd been fiddling with the settings and had selected it in the infotainment charging menu. Took a while to figure out the issue.