are there opportunities for unifying / deduping shared functions

[chrisbc]

IN our team code review last week (ref #37) we identified that there may be some duplicated code in places where we manipulate and transform geometries etc.

This ticket is for Charles & Andy who are the main authors of these functions to do a more detailed review over these modules to see if there's some simplification of the codebase available.

If so, we can create specific issues for the code refactoring task(s)