Ooooo i like this one - i had a little project myself many moons ago - check my posts i did accident repair on mine about 3-4 year ago.
Have you sorted curtain airbags ok? Mine were blown too along with side seat side airbag.
Regarding sat nav - hold off with the dealers and try a card off ebay? Did the car originally have sat nav enabled and the sd card has simply been removed? Does the system say nav when first loading up / screen popped up? My sat nav card was removed but i got lucky off ebay. I bought a 2015 card which didn't work and as last ditch attempt i bought a 2013 card which worked and has worked ever since. 2013 is the year of my car so might be worth trying a card that matches the year of your car? Mine was about £30 - worth trying before spending £££ 200-300 quid at the dealers........ I may have just got lucky who knows but worth a try, just make sure card number starts 8VO and the version matches your car year.
Hope the rest of the repairs go well for you!