Andrew,
I am in the process of a full restoration. For the electrical, I found Dave Irwin in Washington State. https://www.datsun-240z-upgrades.net/ He may not be able to remove the dash, but he is an absolute Datsun Electrical Wizard. I ended up sending him my dash harness, engine harness, and body harness and he went through and tested each connection and replaced the ones that needed to be replaced. He refurbished the gauges including upgarding to LED back lights. He refurbished the turn signal/head light assembly, converting all the side markers to LED and other things. He was great to work with and responsive to requests and had great suggestions. He even converted a hazard switch to an A/C switch so that I could put that in the open spot on the dash next to the hazard switch. He really was great and his prices were very fair, possibly undercharging what he is worth. I cannot recommend him high enough!!
Good luck, Jon