You can either check a bag into the cloakroom or else you can leave it in your handbag or pocket if you want to keep it close by. It must not be removed from your bag/pocket until you are leaving the party. If you need to book a taxi you must do so in the entrance/cloakroom and away from the play areas.
Below is per our T&Cs:-
Members may not take or make phone calls and phones should be in silent mode whilst at an Event. Phones may only be used in designated areas.