PPI is an insurance contract, usually concluded when you receive a loan or credit card. The law states that this contract is an asset in bankruptcy, as is the right to file a complaint in the event of an improper sale.
You must inform the official recipient if you have withdrawn your PPI before going bankrupt. This is because the right to make a claim arises when a PPI or other product was initially mis-sold.
This is the same as other financial products that have been improperly sold, including other loan and credit card protections, bank accounts, interest rate transactions, and loans.