Tidy-up of the comm class

Issue/feature addressed

Tidy-up of the comm class and subclasses

Proposed solution

• Remove unused function SendRecvReplace
• Remove unnecessary virtual function v_RemoveExistingFiles
• Makes function ordering consistent across files

Implementation

Tests

Suggested reviewers

Please suggest any people who would be appropriate to review your code.

Notes

Please add any other information that could be useful for reviewers.

Checklist

• Functions and classes, or changes to them, are documented.
• [ ] User guide/documentation is updated.
• Changelog is updated.
• [ ] Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• [ ] License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).