GP
The story about the officer taking the declaration as a yacht is certainly in several Customs (history) books and my memory is that the officer had to do some explaining to the Board (of Customs - ie HQ) thereafter. Pretty sure there is a photo of the declaration in the Customs museum display in Liverpool. The old Customs HQ in London definitely had a photo of it on the walls, along with Robbie Burns' staff report and other 'gems'
Good improvisation or more likely that was the only form he had in his bag!