We could prove that the application has been received by the DVLA and that the tax has been paid. It's just that the registration does not appear on the dvla website for (up to) 10 days.
If I can't drive it then I am paying road tax for a vehicle which I am not allowed to take on the road.
I already know what the registration numbers will be as the manufacturer has already notified us. Number plates are already fitted.
Does any of this make any difference?