Thanks! I understand now. I was able to flash with the img provided using the instructions above (Debrick via Uboot - GL.iNet Docs).
I then found that the factory img did not contain luci so I had no web UI.
So I did:
scp openwrt-ath79-nand-glinet_gl-ar750s-nor-nand-squashfs-sysupgrade.bin root@192.168.1.1:/tmp/
ssh root@192.168.1.1
sysupgrade -v openwrt-ath79-nand-glinet_gl-ar750s-nor-nand-squashfs-sysupgrade.bin
However, this also doesn’t have luci:
root@OpenWrt:~# opkg list-installed | grep luci
root@OpenWrt:~#
This is a bit off topic now - but I do I understand correctly that I should install luci manually for this image?
Thanks again for your help.