Check the Insolvency Register and see if your name and details are on there. If they are and the status is current, then all the contact details for the OR that dealt with you will be listed.
Then you can call them and see what stage your bankruptcy is up to.
If you are not on there, then you have been discharged. If you need proof, then you need to contact the court you were made bankrupt and ask for a discharge certificate, which you will need to pay for.