"Demetrius Zeluff" wrote (snipped)

Does anyone know how to get around this problem?

Get hold of a typewriter and some A5 paper. Type up a note to yourself
from 'the photographer' saying "sorry but all my negs were destroyed in a
fire in 1976 so I can't provide you with a copy, but if you have the
original photo you could take it to a highstreet developer who should be
able to make a copy for you."

Then give it some inscrutable signature.

The technical name for this is forgery. Forgery is a criminal offence.
Breaching a decades old copyright is not. I would suggest that you use
technology to overcome your problem.