I looked into “how to start a policy before owning the car” online, and while I couldn’t actually find the answer to that question, numerous pages were telling me to get all the quotes beforehand and start the one I chose by telling the insurance company beforehand to start on the day I pick it up.
They were all Strayan pages, so it seems others are as surprised as I am that you can’t take out the policy beforehand.
I wonder if this is just a Lumley thing? Or alternately, I wonder if calling them back, which will likely have you talking to a different person, will get you a different answer?