My Daughters Infiniti Q30 electronic steering control unit has failed and there is no spare parts availability in Europe and according to the dealer she bought the car off (its under warranty) Infiniti ceased selling cars in the UK in 2019 so well within the 10 year obligated spare part supply period. Nissan cannot give a date of when this part will be next in stock so couple of questions...

What obligation does the car dealer have to provide a courtesy car until repair is done?

What obligation do they have to offer a re-fund / buy back (minus the 6 months of ownership)?

Garage have stated that they wont fit 2nd hand parts as the warranty won't cover this

I have found the original manufacturer of the pumps (based in Europe) but they have a minimum order quantity (quantity tbc) but feel this could be a dead end and its more than likely the place Nissan but them from when there is enough demand

This is potentially writing off a 8 year old car with less than 50,000 miles, we could at our cost take it to another garage and fit a 2nd hand unit (no guarantee it will work) plus this invalidates the existing warranty and leaves her open to this fiasco if the unit fails again