The client should still be able to view the documents on the completed record, it is after all a record relating to the client. The workaround you have detailed means James will have to import documents from the completed case to a new case which may or may not be relevant, because actually they are not valid for use with the new case i.e. historical bank statements, expired documents etc which just clogs up the new record unnecessarily.

So whilst I understand this is a workaround to get this sorted on this one case, clearly this is a much bigger issue that needs to be resolved with the system development team (something else to add to the list).