Well having written earlier in the week that the software update so far hasn't been available, I tried again after receiving the e-mail from Jaguar, and surprisingly the update to 19B was now available. Tried once to update, but seemed to fail. Tried again the following day and monitored the 4G mobile data to see if something was happening, took around 35 minutes to download around 200MB. Got a message it was installing, so left it overnight. This morning, checked again and said the new version would be used following the next shutdown. After waiting a couple of hours, it is now running 19B. I have the 8" screen, and a quick look suggests little visibly has changed, but one less thing for the dealer to do at the service.