I don’t think one can order a new vehicle before the renewal window is open. Also as you are on the old contract and have significant adaptations, you should be able to extend your contract for up to two years (five in total), unless you are settled you want another vehicle.
My renewal window is 29/08/2025-29/11/2025 so I’m within it. I’m tempted to just renew as this is proving to be a lot of hassle!