How to fix iOS 10 Public Beta download fail

I’ve been trying to download Apple’s newly-released iOS 10 Public Beta software update onto my iPhone SE, but it constantly failed.

After installing the update profile, the software started downloading OK but then failed just as it was about to complete.

Tried many things to make it work and eventually found this:

Install the Opera VPN app from the App Store and follow the instructions to change your location. I changed mine to the US….I’m in the UK. 
And it worked. Phone now has iOS 10 Public Beta 1.