This is followed up with a supplementary declaration within 14 days of shipment.

The Supplementary Declaration for the goods must be submitted electronically within 14 days of shipment.

For most simplified, incomplete declarations the linked, full, Supplementary Declarations must be submitted within 14 days of shipment.

Simplified customs declarations - if you are authorised to use either the local clearance procedure or simplified declaration procedure, you must make your abbreviated declaration under NES into the central CHIEF system and then submit the final details within 14 days of shipment.