My landlord's deposit claim went up after I refused to settle privately. What happens now?Beta*

This happens more often than it should. An adjudicator looks at whether each deduction is backed by evidence. The landlord needs to show what the property was like at check-in, what it was like at check-out, and what it cost to fix. A claim that suddenly grows once you refuse a private offer will be judged on that evidence, not on the size of the number. Answer each item separately and point out where the landlord has no check-in evidence. Point out wear and tear, and anything that makes the place better than it was when you moved in. Keep your reply factual. The landlord can't take more than the deposit through the scheme. Anything above that, they would have to claim from you in court.

Sources: Shelter: dispute unfair deductionsmydeposits: dispute resolution for tenants