you can have your salary paid into a 3rd party's existing account whilst bankruptcy is petitioned for and dealt with by the OR.
Or you have to get the timing right. Have a Co-op account set up before declaring bankruptcy. Time your court appointment for a day or two after pay day. On being paid, but before the court appointment, remove the money. Declare bankruptcy. Next inform your employer of the new bank details for your next salary to be redirected and also any supplier which you will continue to pay by direct debit.
Inform the OR of the existence of the new account.