I have only one ex rental print to the best of my knowledge and even then, I am unsure whether or not it is a Derann ex rental print.
The one I have is the full feature of The Way We Were starring Streisand and Redford.
It's a print I don't believe otherwise ever made it for actual sale release on Super 8mm so as a very big Streisand fan, despite some fade and a little wear and tear, it's one I'm still pleased to have now on Super 8mm.
What Tom speaks of above was merely the specific restraints by the film companies in allowing companies such as Derann to distribute such films and as a result, collectors to own ex airline optical sound prints which is something completely separate but linked by the actual outcome being something of the same due to copyright protection in these instances.
Most (if not all) of what i read in Derann's second period of film hiring catalogues, were films they already had the rights by the film companies to distribute as they were all titles they also actually sold similar prints of to their customers.
When I find myself a little spare time I will photograph the later hire catalogue and all of its contents and post them here.
It was very much an abbreviated version of their actual sales catalogue in many respects, except in one or two cases it also featured titles that at that time, were by then obsolete as they had found themselves "out of print" as the rights Derann had obtained for some from the film companies had expired previously some time ago.