My expectation would be:
You will be assigned a VIN (usually about when the boat reaches Suez). Only thing that will then prevent you getting a car is some sort of upcock, or the car being damaged in transit / failing PDI. So being asked to, and making, payment is basically not going to then be pushed back. But don't hold me to it!
payment window-tod-delivery is about 7 days if all goes well. I've paid at 15:00 day before collection (repeated errors on invoice) for collection at 09:00 following morning ... (ask about how to make sure they have your payment before you set off for collection! if that happens to you)
... if you are paying cash then your bank may limit how much you can transfer each day, so may take several days to pay it all
"very similar spec" is not the same. Could be in completely different build batches.
Unusual for prioritisation for
identical spec to not favour first-come-first-served. However if someone after you has included FSD and you haven't then that is
not "identical spec". I'm not aware that Tesla is allowing that sort of queue jumping to occur in UK, but adding FSD to order has been a means of queue-jumping in USA.
When Model-3 first arrived in UK I got one of the early ones. I had no "day-one reservation" or anything like that. I just placed an order when the order book opened. I'm a long standing customer, so if I assume that had some influence then "anything like that" might cause "allocation" and thus queue jumping.
Cars are
not made-to-order, they are made in batches and then allocated to orders. So all thoughts of "I don't understand why X is in front of me" have no bearing, although generally speaking "100% Identical spec" will be in reservation number order. If you change your order from White to Red then you will lose your place in the queue (but you may get an earlier slot, if there are unallocated red cars that can be matched with your order).
Nope! A deferred collection will free up a car for re-allocation, so there's an extra curricular activity you could indulge in
I have no idea how that is prioritised, but fairly sure that is a manual process "Phone up and see if Customer is in a position to collect". If that's the case clearly they won't want to phone very many people to get a "yes", so maybe "Cash" beats "Finance" and "trade in/Not" carries weight too. Or maybe they just stick it in Inventory and then whoever is fastest-finger-first gets it.
recky