Sorry to hear that you’ve had so many problems. I bought one of my daughters a new i20 Ultimate privately nearly 3 years ago and apart from a couple of minor issues, sorted under warranty, it’s been fault free. It sounds as those yours was a Friday built one! Our Hyundai dealership is brilliant. Both the sales and service teams have been first class, both as private and Motability customers.
Funnily enough, it was the heated steering wheel that featured highly on my daughters wish list (she’s a Police Officer, so works shifts) and it’s one of the few things that I’d miss about our Tucson!