Its a Mobility car, so your direct claim is through them not Nissan however, Motability don’t don’t claim to offer a like for like hire car, other than they will do our best to give you as suitable a replacement for your needs.
“Most replacement vehicles are small five-door cars. If this is not suitable because of your disability or adaptations, please mention this when you ask for a replacement. We might not always be able to give you something that suits your needs, but we’ll offer you alternatives.”
https://www.motability.co.uk/get-support/if-something-happens/cars-wavs/replacement-travel/