Mark, it was in the early 1990s from memory.
I believe the principle is that if a case is specifically physically marked then that case is the property of the customer. If it is damaged in store then the customer will have to claim on insurance or against the bonded warehouse.
Normally wine merchants don’t mark cases so good cases are withdrawn by the warehouse as long as possible and then any broken ones are all sorted out together in one claim. Hence in this case the court decided that they formed part of the merchant’s stocks rather than the property of the customers concerned.