Hello Deano and Lou, I'm having similar trouble with the Starlink SD update for my 2015 Outback. Just been on phone to my local Subaru dealership in Sheffield who tell me that the system is to buy a replacement Micro SD card from their parts dept, with the updated maps. Only trouble is it's coming up at £459 !!! Told them that was more than my insurance and I won't be paying it. To be fair the guy in the parts dept was shocked at the price as well. Would love to hear your outcomes and how they were achieved and at what cost please. I have the micro SD card and that holds the map data - when its removed no maps available.
