He says the Zs are too high though, not too low?? Which row is that on the report?
EDIT: Okay House sockets is the 2.1. Kitchen sockets is 0.00, so yes, that would be tripping the breaker repeatedly right, because it's a short circuit? The tenant would certainly have noticed and reported that. Pretty poor that the unit of measurement is not stated too.
In his point 2 he mentions two things, ir at 0.0 (which is wrong) and the high Zs - he doesn't mention the value here, but it is in the table of test results under "measured Zs" at 2.49 ohm. This must be less than 1.1 ohm (max permitted Zs) for this circuit, which it isn't hence the high Zs comment.
His ir at 0.0 is actually both 0.0 and 2.1 somethings in the live-earth column
It cannot truly be 0.0 as this wouldn't just operate the RCD, but would be a major "bang"
I suspect he measured it on the IR setting and never actually measured it again on a more appropriate range.
Technically it is possible to get 0.0 but not trip, as the normal voltage is 230V whilst the test voltage is 500V - so 500V could cause an arc, and show as a short, but 230V may be insufficient to arc, and therefore not trip - although technically possible it's practically unlikely.