Well, reinstalled and I selected refind as the bootloader, and basically nothing happened. My existing refind still didn't find it, and I still couldn't booto it. So I reinstalled again and selected systemd. This time a .efi file appeared in the systemd folder in the EFI partition, Refind found it and I can now boot Kaos. Only tiny fly in the ointment is that it boots into grubbish looking screen with a couple of choices on it, and I would prefer it booted directly into Kaos, but I can live with that. Still no idea where the vmlinuz/initrd files are, but I'll h ave another look later.
;-)