Thank you for looking into this so quickly.
I updated the licence as instructed, tried my upload again, it failed as before.
I did a reboot on my computer, checked everything on the program again, and this time the upload completed. It did stall at 70% for a while, but then it carried on and finished.
I'll be working with it today, I'll see how things go and report back.
It's -36 here this morning, so I'm a little slow in getting out to the shop.