OP
Understood. I’m sure if I ask him to install something he knows nothing about then he might challenge it.another ting to consider is this..... your electrician will have his preferences and for the boards he usually installs will have spare RCBOs, and have a rapport with suppliers as if anything goes wrong, replacements will be readily available. that's related to my post ~28
Again thanks for everybody’s help I think I have enough to short list.