@m4d4dsm
It does not say “delivered,” please re read, i have posted a screenshot, it says order placed and registered, ( so marshalls get the brand bonus. Cars are registered long before delivery, if you encounter any difference, then this is a false offer, as no new car is built and delivered in a month. (Esp bmw), So, as long as you show the offer as in the email, you will be ok.
Further to add, the £500 discount is not applied at handover, it is deducted from your order, when you place your order, ie after new car bonus, any extras, any deposit, ect, so that figure, is what you pay. You can pay it on order or on collection.