Insulation resistance query old style hager rcbos

[Questforknowledge]

When carrying out insulation resistance testing on old style rcbos (hager) I understand you are supposed to disconnect both line and neutral aswell as both the neutral and functional earth fly leads.....however does this in theory mean you need to disconnect the above for all rcbos at the same time.... If so this would present quite an issue when testing a modern rcbo consumer unit

Thanks for any replies