I've just done the update. I copied to files to a microSD card, double checked the md5 checksums, then used a USB adaptor and plugged into the car.
Once at the the system info page on the HU pressed 'update', had to chooses between 'quick' and 'general', so selected 'general'. First off it took a few minutes to verify the files, then about 50 minutes of 'Updating'. When it got to 98% it just went back to the system info screen and nothing updated, so I selected 'update' again and 'general' again, and this time the radio went off, and a message saying it would take 15 mins to perform the update. This time after getting to 100% the HU rebooted and the update had completed.
It now has a very different look, driver profiles etc etc, maybe a little less intuitive adding radio stations, but I easily got the ones I listen to added to favourites. Bluelink setup asked to input my phone number and sent a sms code, after that Bluelink was working straightaway again.
Spent about another 15 mins getting my preferences tweaked for driver profile etc. and looking at options. Distance had been changed to km (not miles) on the other display in front of driver, so I searched for 'km' in the HU and found which setting changed it back to miles.
Haven't been for a drive yet, but I'm sure I'll find everything needed when the time comes.
Many thanks to
@SonicSpinner for the files and advice.
PS screenshot...
View attachment 32986