The police will probably not be interested as they will consider your situation to be civil law, they clearly do not believe the threat allegations and it would appear there have been previous false allegations. Make sure your solicitor is aware of the position and have each allegation reported to the court. Someone who causes wasteful employment of the police by making a false report commits the offence of wasting police time, but you may have difficulty in making the police take action.
Have the court granted you a contact order to see your children? If they have and it is dated after December 2008 it will contain a warning notice, if you are getting constant excuses from the resident parent over why you may not see your children report each occasion to the court who are becoming more robust with continual excuses from the resident parent.