I think it has been mentioned before, but I cannot find any recent references about this subject.
It would be nice to have a unique ID number for each transaction. The number would be generated by the program. I am sure there is possibly one already, hidden from users. If we could have access to it, as long as the number is humanly manageable. If not, it could be another numbering system.
The current Ref # is not suitable as it is, since we can leave it blank or enter any text we want. If the number could be created automatically by the system it would be good. It might also be good to keep the Ref # as is, but add a new field which would be ReadOnly and could be displayed and used as a reference.