Loan providers must allow you to pay back a personal loan early in full, but they can charge you an early repayment charge (ERC). Early repayment charges vary, but typically you can expect to pay the equivalent of one to two months’ interest.
Any fees and how they’re calculated should be set out in your loan information and agreement, so you know what to expect if you repay early.
Plus you do not have to take the personal loan for the full amount. You could pay a larger deposit and even if you do have to pay 3 months interest it may be lower than the £1000 deposit contribution. You would have to see the terms and conditions and mess with the numbers.