1. You seem unsure what happened to the house. You ought to find out, but it is likely that if it was repossessed the sale price was insufficient for your charge to be paid off (i.e. the mortgage lender would have taken all the proceeds). However, you should have been notified at the time.
2. If he owns his present house and is bankrupt then he is at risk of losing it. If there are any proceeds (other than those to pay off the mortgage) then they would be shared between the creditors after the OR has covered his costs.
3. I assume you have found his entry on the online Insolvency Register. If so, you will know which Court he was bankrupted at & can find out which OR's office is dealing with him. As it was only last month, it could be that he put your debt down on the form but that the OR has not yet got round to contacting you. However, even if he did not put you down on the form your debt is included in his bankruptcy and you cannot chase it in any other way. Contact the OR & give details of the debt. But I suspect you are most unlikely to get any money.