I believe it's the invoice number, not the reservation number, that dictates your "order number". My reservation is xx2388 but my invoice is xx0280. I ordered within 15 minutes of receiving the notification email on 9/29/21. If it is res number,
@MurphyMurph having 0961 with a 2023 reservation date would mean there's something goofy going on. I wish it were more transparent with the explanation from Ineos which number it actually is. They keep saying order number but that isn't the wording used in any of their comms.