Tidiness is a good practice, does not mean its unsafe. Did he do a full wiring test before changing the CU? I don't think you can just go and change the CU without doing a full test, as that will classify as an installation and should be notify. The test will help you to identify any wiring issue(s) and correct them before making the change. This will eliminate any issues like tripping. Any un-use MCB should be taken out and blank off not tape off, just good practice. I will not leave any flammable material such as paper under the bus bar, any arcing due to loose termination is a fire risk. You need to get your husband back to the job to fix any issues related to his work, its only fair to the client.
