Despite you being the module implementor and its only user, I still feel it's good discipline to maintain a clean separation between interface and implementation

Whilst I am the module implementor and only user, one or two other people will probably be involved in using and developing this module in the future. However, it will never be a public module as its functionality is useless outside the ecosystem for which it was created.

Normally, I do add POD at the end of a module, as you suggest.

The question comes about here because the module is updated very frequently and evolves to meet changing needs in the rest of the codebase. This seems, on the surface at least, to warrant having the POD for each method next to that method.

Having read the various comments, I shall try interleaving POD with code. It is not exactly going to be hard to group it all together and relocate it to the end of the file if I find issues with this approach...