I have to ask the question that if you have all these problems with your mother, why are you still speaking or having contact with her or indeed, travelling with her?
Don’t let’s abandon this just yet. What exactly is it that you want to know about this?
The chance is remote unless they fabricate evidence. If you are prosecuted, you are prosecuted and evidence which proves your guilt beyond reasonable doubt and if you haven’t done anything, there cannot be anything other than reasonable doubt or indeed, infinite doubt.
You may be arrested on suspicion and questioned under caution but you are still likely to be released pending police enquiries.
They can’t tie you up in litigation of a criminal nature unless they bring a private criminal prosecution which in all honesty is very difficult and usually not very successful. If the police are not interested in prosecuting, private prosecution is rarely going to succeed.
There is nothing illegal about recording someone’s voice although it’s only admissible in court if it’s in the interest of justice. I can’t see that it would do any harm except that you may find that if the person discovers you have done that, they may take great exception to it. You are only doing it as a way of self-preservation after all.