IMPS07530 | Onward supply relief (OSR): verification of goods imported for onward supply to another member state: assurance action by verifying officer
From HM Revenue & Customs · Import VAT Manual
As verifying officer you must be satisfied that the goods have been supplied onward to the EC consignee, by comparing the information given in DE 3/40 of the declaration with the importer's commercial documentation and accounting records.
Acceptable evidence may include:
orders from/correspondence with the EC consignee (showing their name, address and VAT registration number)
payment from the EC consignee
instructions to the agent
arrangement of payment for transport to the member State of destination
entry on the EC Sales list.
Many entries to this relief will be from freight agents acting as a principal for an EC consignee. In these circumstances the freight agent must enter both the import and onward supply through his records. This is essentially a paper transaction since the EC consignee will not be paying the agent for the goods. However, evidence of onward consignment held by an agent may be expected to include:
correspondence/instructions from the EC consignee (showing their name, address and VAT registration number)
payment from the EC consignee for the agent’s services
arrangement of payment for transport to the member State of destination
entry on the EC Sales list
airway bills/shipping bills proving transport to the next Member State.