Technical debt/future considerations

[ollieread]

This is all the “technical debt” or future considerations off the back of the initial work.

• The unit tests can be refactored to use mocks and fakes over models and actual database entries.
• The ServiceOverrideManager will need a dedicated unit test
• I don't like the current documentation, as it reads more like a technical breakdown than a walkthrough like Laravel

[ollieread]

Address test coverage mentioned here: #112