How do I find out if my Son's mum is trying to get a passport for my son? I know she needs my permission but can she go though court without me?
First of all you need to provide some more info about your divorce / separation or your current relationship to the "Mum".
I will try to give you some advice and from my personal experiences :
Do not go to court unless you have solid evidence that "Mum" is trying to obtain passport for your son , without your permission which you said "she needs " . Why does she need your permission ? Do you have legal separation agreement which says that without your consent she can not obtain passport for your son? If not then there is nothing stopping her from doing so , you on the other hand can go to passport issuing office and tell them that you do not agree with your son having a passport because ...........I am sure that they will put a stop on the process of issuing him a passport , until you agree to it , or she has some sort of legal document stating that your word in this matter means "nothing" ( unlikely scenario ) .
Have you considered asking her straight up if she is trying to obtain passport for your son?
Now , as I said earlier without knowing more about your relationship to "Mum" and legal agreements between you two regarding child custody its is impossible to give you solid advice . One more thing , no matter how badly you hate "Mum" and how badly you want to screw her life , keep your child matters as priority #1 please .