The problem is he closed his bank account when he went back to AUS, his phone bills he never changed the address since it was all digital, and his employer didn't change his address either. If I contacted my landlord to request a back dated lease agreement... would that work? Is a back dated lease agreement legal?The issue is that your proofs don't actually show 12 months of cohabitation. If you go with what you have, I would expect a Procedural Fairness letter. He should be able to access his bank statements and old phone bills; printing out electronic statements is fine as long as they list the address. Contact the former employer and ask them to email his old payslip (assuming they show the address).