lou a few points £3000 payment up front being half the advance payment £6000 is a lot what did you order .
you do not need to pay anything up front you pay when you collect the car, yes you can cancel the order up until you enter your pin, will you get you 3k back it will depend on the dealer and what you signed , i would say yes , contact the dealer tell them you want to cancel your order you dont need to give a reason .
the dealer might say you need to pay for the extra or there is a cancellation fee ,
if they dont give you it back contact motability .
when you order your next car dont pay anything until the day you collect it providing your happy with the car
hope this helps