It likely is going to fall under child neglect. I don’t know of an actual law specifically for locking a kid in a car.

As for the exceptions thing, that is the same in the states, it usually falls under law(s) categorized as “Good Samaritan laws”. They are moreso meant to protect the bystander if they see someone in peril but, breaking the window to save a kid or pet that is clearly in distress would normally fall under that. Personal injury also usually fall under these laws, like if you accidentally injured someone getting them to safety when it was clear they were in a dangerous location, the laws usually apply.