Yeah, can’t knock them in that regard – if you call them and explain your change in circumstances, they’ll accommodate you. You’ll probably immediately get asked if you want to terminate the contract early (incurs a £50 fee though), and you can order a new car the next day.
I don’t think they’ll offer you a courtesy car, you’ll probably need to continue driving your current one until you receive the replacement, so i’d be starting to call dealerships for delivery times and potential stock vehicles just in case.