@dave.m.brown,
Your disk configuration does not look like a standard Win 10 UEFI system.
The EFI partition looks correct, can be 100MB or 260MB depending on the type of disk used, but I don't see a system reserved partition here, that is usually on a legacy BIOS not a UEFI ?
The Microsoft Reserved Partition is usually 16MB and you don't see it in disk Management, see Diskpart command below and the display with another utility.
DISKPART> select disk 0
Disk 0 is now the selected disk.
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 System 260 MB 1024 KB
Partition 2 Reserved 16 MB 261 MB
Partition 3 Primary 475 GB 277 MB
Partition 4 Recovery 1000 MB 475 GB