Comment 2 for bug 1909365

I seem to have resolved this and got a full install after a couple of restarts. I notice that on the last 'successful' restart, the empty disk had some partitions created - and this seems consistent with googling similar errors and advice to create the EFI partition first.

Not sure what happened, but I assume the problem was that it was a completely fresh and unformatted disk that was causing the installer to hang.