See VAT1615A. The vehicle has to be substantially and permanently adapted alongside being for a person that normally uses a wheelchair. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/605061/VAT1615A.pdf
Yes, that’s what we are using as a private buyer, but Motability get a block VAT exemption on ALL of their cars, so these rules don’t apply to them, hence the question specifically about the options.
I can only assume that their exemption to the above rules only applies to the basic vehicle price and not the optional extras. As far as I know, Motability customers still have to pay the full cost (inc VAT) of all factory options (not disabled adaptations) even if they meet the criteria that exempts private buyers from paying the VAT?