Thank you for the question.
The first part of your question refers to the seriousness of the offence. I would probably put it in the same category as criminal harassment. The offences related to coercive control will probably come before an offence involving bodily harm, since coercive control often occurs before acts of domestic violence, to use your example. I would therefore place it in that category.
In terms of evaluation, the police officers would of course have to be trained after the provision was put in place and they would have to have evaluation tools at their disposal. For example, in the United Kingdom, a risk identification, assessment and management tool called Domestic Abuse, Stalking and Honour Based Violence (DASH) has been developed. This tool allows police officers to properly assess coercive control.