My husband rewired our old house when we bought it first, then got an electrician to come and they walked through all the work, and electrician acknowledged it was safe.
When we did an extension and improvements In the house a registered electrician did the wiring etc and our engineer signed off each part of the build.
What I am trying to say is do the work yourself to the current standard and get a professional to certify it has been done to the current regs. You probably know plumbers and electricians who will take the time to walk through it with you and approve it.