Trader presents a Carnet, however, the previous transaction has not been recorded in the Carnet (i.e. export from France on return to UK, or import into UK but the goods are now being re-exported. Can I still endorse the Carnet for the transaction presented to me?

Yes. Officer can process the Voucher and Counterfoil as usual, but state “processed without prejudice as previous transaction not recorded” in Remarks box.