My continuity readings continuously reading zero when measuring R1 + R2, My meter may not necessarily be faulty?
Regularly zeroing your leads is now deemed common practice as part of your periodic checking and risk assessment protocol, with a lot of electricians expecting their leads to last the life of their test equipment. Test leads are a wear and tear items, commonly, subject to lots of stress in arduous environments with the crocodile clips deteriorating over time. The spring that connects the top toothed track to the bottom track can breakdown, causing the top track to be more resistive than the bottom. This issue really only becomes an issue if you zero your leads using the top tracks of each crocodile clip, greatly increasing your lead resistance.