Well things are not going too well!
I decided my m2p image must be corrupt so decided to download and re-burn the SD card. I followed all the instructions up to the point where I hit „Write“. I then get a write error „An error occured while attempting to write data to handle. Error 5 Access is denied.
I think this is a Windows 10 permissions problem, I ran Win32 Disk Imager using „Run as Administrator“ – and my account has administrator status. This made no difference – sill Error 5 Access is denied.
I formatted the card and it is now available as a drive in Explorer, and I can save files to it.
What do I do next?