In my opinion if I were in your shoes I would tell the insurance company that the lighting circuit/s need to be rewired why delay the inevitable they are going to have to be rewired in the coming years and now would be the ideal time it annoys me when people try looking for ways out of doing the sensible and right thing tell them that you are going to be the one to certify the work and don’t want any repercussions after you’ve left the job. They’ll be quick enough to point the finger at you if anyone had a belt after you’ve left.