Glad my question found the right location in the end.
I thought I would reply here just for completeness. I ultimately wanted to know how I can avoid file duplication in my own local repo when sharing application files between modules. The answer on StackOverflow suggests simlinking directories between modules is the only way to go. As Nick suggests I could store my file data in Cloud Storage or the datastore but I want to avoid the complexities of that.
I'll accept the StackOverflow answer unless anyone has a better suggestion.
Best wishes,
Dan