who do I contact to get a police check?

Answer 1

Where I worked, it was called a Special Attention. The reason has to be legitimate though. Constant criminal activity, house will be vacant due to vacation, etc.. You can contact the desk Sgt., and explain the circumstances. Unfortunately, the check will only allow the Officers to do this when they are available.

Answer 2

Depends on what the check is for. If you are an employer, you get permission from whoever it is you want checked. You are getting into privacy matters if you don't.