Full payment before PDI?

Booked my sig+ on December 12th The car was finally allocated on 9th Jan The dealer is asking for the full amount payment by 16th Jan(7 days for day of allocation) They are saying that the allocation will be revoked and given to next customer in line if payment is not done by that day

The car is still in transit and probably not reach the yard by that time

Is it fine to day the full amount or should in push it after I do self PDI in yard?