As always, some interesting points raised by Calluna4u.

With regard to final consignment being +/- the expected (stated) number, do you think that the people that you've heard of who fail to report their imports would look differently at the paperwork if there was facility to make the pre-arrival declaration but then to have an 'ammendments' window of a couple of days to clear up any discrepencies. Probably too simple a solution where government paperwork is concerned, of course.