Sorry for putting too much in. In brief, Uboot is still broken. I saw suggestion online to try the following command line to see if it revealed anything and it appears there has been some issue… I’ve removed most of the output to just include what I think may be most relevant.

root@GL-MV1000:~# strings /dev/mtd0 | grep U-Boot

UPDATE FAILED

Something went wrong during updateProbably you have chosen wrong file (too big or too small) or you were trying to update ART on device with unknown FLASH…

U-Boot 2017.03-armada-17.10.2-gc5a0d2c (Sep 01 2019 - 18:20:09 +0800)
U-Boot DT blob at : %p
Warning: U-Boot configured device %s at address %llx,
U-Boot
** Invalid partition type “%.32s” (expect “U-Boot”)
U-Boot BUG at %s:%d!
Upgrade type: U-Boot
U-Boot EFI: Relocation at %p is out of range (%lx)
No valid device tree binary found - please append one to U-Boot binary, use u-boot-dtb.bin or define CONFIG_OF_EMBED. For sandbox, use -d <file.dtb>
U-Boot.armv8

Does anyone know from that what I might have done wrong and any suggestions for a fix? If there’s no easy answer I’m happy to be directed to some learning. I have seen a few videos on U-boot but that all areas to be around the use of the UART serial connection and into the uboot shell which I think is a bit beyond me.