I omit the poor solution of your connector (there is no disconnector on the power supply), the diagram is not true, because when you have a connector a meter from the pole, nobody made two separate groundings, as there was a normal contractor, it went to the ground at the pole (10 ohms). You have a grounded PEN in the connector - (because these are the requirements for the construction of LV connections), therefore the yellow-green from the power supply "goes" to the bottom of the connector, there it is connected to the hoop on the trestle (insulator). The fact that you also have a separation on WLZ - this is a mistake, I omit the use of the grounding of the distribution company, but you are not able to measure the value of this ground without unsealing the power part. It may well be below 10 ohms and 300 ohms. How will you know that ???? Unfortunately, not all of them measure earthing at the receptions of the connections, I ignore the fact that after the connection is made, the time of its foundation is set to +/- 15 years, the earthing may be different after this time, depending on the protection of the connections.