[Janitorial] Sonar / Pylint clean up initiative

This issue is to track ongoing efforts of sanitising the code base, remediating issues raised by Sonar & Pylint after the minimum python 3.10 configuration change, ultimately to get our quality gates passing again.

As well as review the status and feasibility of the existing multiple clean up branches that have grown stale:

This initiative will be in quite conflicting and will likely require scheduling and code/development freeze to be successful.