(ENG) Current address has been a sublet without permission for a year - what to put for current address now moving legally?

As title says, so happened was just looking for short-term but ended up being ages, now moving in somewhere through an agency and need a current address/proof of address for the referencing form. What would be the best thing to do here? Live at home (even though far away)? Tell them the truth?

Thanks for any advice.