I honestly don't think it will be custodial!
What you need to do, is either, not attend court, OR if you are summonsed, take the oath and say" Good morning to you and your colleagues, you will note I have answered the conditions of my witness summons and will now leave the building". They cannot force you to give evidence.
Unfortuantely due to this happening so often to police will attempt to prosecute you for wasting police time if you do retract, therefore it is now only possible to let things run there course and learn for the future.