Any way I think i've managed to get it working, so thought i'd post to share with anyone else on EE.

SD Card music - my car has the Dynaudio speakers - which sound outstanding to me. I wanted to give them something high quality as a source. CDs sound incredible, but so do does high-quality digital music files from the SD card. This lives in Slot 1 now, and has all my favourite music on it. I know most people now probably don't have a digital music collection like this, but I still do, so might as well use it. To my ears, it sounds better than either bluetooth-based audio, or my wired Android Auto phone using high quality Spotify streaming. Its also very easy to get to the album or artist you want, or just to shuffle the whole thing.If you don't have the discovery nav you can still just use the mini wi-fi router to create a network without having to go through the head unit. The Discover Media happily connects to the Huawei modem, seems to be getting all the correct traffic updates, CarPlay is streaming music etc. Personal Hotspot on and linked to car. Both phones paym contracts allowed data sharing without any setup or cost. Siri works very well, activated by voice dial button on steering wheel using the car microphone. Functions better than my previous Golf which had voice control.

Possibly the DNS may use the Internet connection (*) to update traffic en route. It also uses traffic info via the radio system. I don't have a smart phone at the moment. I'm trying to decide which one to buy and which SIM plan to get. I'm leaning towards an Android phone though. VW UK Customer Services say that they receive fewer support requests from drivers with iPhones than they do from drivers with Android phones. When I pointed out that there are probably about four times as many Android phones in the world as there are iPhones, they couldn't comment any further! Plugging it in with hotspot enabled then forces it to connect and it continues to work after unplugging.

Apple maps works well as an alternative to the DNS on board satnav. Great with Siri voice control, as is the iPhone dialler. Car-net iOS app has basic functions away from the car, one of which allows destinations and poi from this app to be sent to DNS. You state "Personal hotspot on and linked to car.". I'm sorry but I don't understand this. I am assuming that you have not configured your iPhone as a WiFi hotspot and that the Infotainment system does not connect as a WLAN client. So what is a "personal hotspot" in relation to an iPhone? It is really getting off topic to discuss the relative merits of the iPhone and Android phones. I’ve been a Luddite for many years and have refused to buy a smart phone. However, my elder daughter has an Android and is very pleased with it, and my younger daughter has an iPhone and is equally pleased with it. And, having watched them use various useful apps on their phones, I’ve been persuaded to buy a smart phone.