OK, I got it sorted now.
https://downloads.lede-project.org/snap … pgrade.bin installed
then used ssh to install LuCI (I found that it defaults to user root with no password).
Now it seems to be working great, however the TP-Link modem web interface seems to be the old one even after I restored to mr200_back_to_stock.bin then updated to the latest OEM firmware before re-installing ArcherC2V1_tp_recovery.bin, installing LuCI and upgrading LEDE again (I am getting used to the procedure now).
One of my objectives is to get accurate stats from each device attached to the MR200 by MAC address so that I know exactly how much data each device is using. There is a stats page in the newer OEM firmware that lists each MAC address but I find that this intermittently resets itself so it is not reliable. Now, after installing LEDE, I don't have anything like this stats page from which I can check the stats for each device.
Is there any way to achieve this?
I already monitor bandwidth from the MR200 using Cacti, but can't see any way of getting cumulative data throughput for each device using that either.