Carista has now arrived and seems like an interesting device. Worked seamlessly with my iphone / ipad and I was quickly able to diagnose and clear fault codes. It seems more limited in terms of functionality than VCDS however I don't have any Windows based hardware to use that. For £32 delivered from Amazon Prime with one month free trial, it has certainly been good value and allows for the easy customisation of door locking etc but cannot access the mirrors / steering / brake assist. Maybe Torque Pro or another app supported by the Carista bluetooth dongle will cover those.