Hi Sui, I renewed my Italain passport a couple of months ago and was initially in the same position as Mrs Sui, ie trip coming up and no appointments on the consulate’s online booking system until months after my date of departure. However kept logging on and checking availability until a cancellation came up. It was within a week and I was in. Early morning appointment and new biometric passport ready within a hour and a half. System appears to be much more efficient than previous experiences (at London consulate).
Cancellations do come up on the system as the penalty for a no-show is being blocked from making a new appointment for a considerable period of time. You do have to be persistent with checking and snap up anything that becomes available immediately, or it’ll be gone.