The higher zs is fine, and dealt with by the application of rcds for fault protection, and in this case since they are 30ma they will also provide additional protection. The curve ball is the 2.64 ohm L-N....generally we assume that if R1+R2 is good then R1+RN would be as well....since the CSA of cpc will be less than or equal to the neutral...but ring finals aside, what specific tests are mandated to check this? Could well be a loose neutral connection, but how are these tested?
Often hear circumstantial evidence that it's always neutrals that burn out or are loose....is it because a loose l or cpc gets picked up during r1+r2 testing, but those pesky neutrals fall by the wayside? Just a thought....