I think you should have been answering @Eric_Fewster rather than me.
I have had exactly the same problem with Green Building Store, as they were then. Also for a door. I asked whether it could be arranged to share a pallet with another customer and I’d collect from their site, but they weren’t cooperative.
So far I haven’t replaced the door but the old one has now developed a fault. It is a thermally broken aluminium door from the eighties (advanced for its time) and I can’t get the spares. I have a Rationel Windows outlet near me and will be paying them a visit.