Assuming that your friend is eligible for VED exemption (highly likely if eligible for a Motability car) then they can register the private car as their exempt vehicle, so they will not have to pay VED, even the higher rates that apply for the first 5 years to cars that were over £40k
Thank you so much for the information Glos Guy. Their lease ends next week, as does mine, So am also considering leaving the scheme as there’s nothing really suitable for me and with the advance payments getting higher, now maybe the time to buy what I love and keep it!!!