New
#11
Thanks guys for replies so far. Update: Downloaded Windows 10 ISO, Created USB stick (FAT32) with Rufus, selected "mbr partition scheme for UEFI". Attempted to install on Windows partition. Same result as before - can't install on GPT partition. This was with BIOS set to legacy mode. Tried again with BIOS set to UEFI mode, no USB boot option available. So - no further forward.
Any more suggestions?