Netgear R6350, recent nmrpflash install, mac address

First time working with OpenWrt

Motivation - stock firmware available from NG seem to no longer support offline configuration without router being plugged into modem (firmware present on device when I received it did, but... gone now, no version tried from NG site seemed to work for me.)

As I was unable to try installing via netgear UI due to issues there, took a chance and
Was able to install image
openwrt-19.07.7-ramips-mt7621-netgear_r6350-squashfs-factory.img
to netgear R6350 using nmrpflash
(The R6350 installation via nmrpflash is not currently mentioned at either of

or
https://openwrt.org/toh/netgear/netgear_r6350)

Haven't actually used the device yet, but I can at least get into the config UI.

Now up against much lack of OpenWrt knowledge and the apparent lack of that build easily specifying MAC over-ride (via UI) which I think is needed to swap in this router for access to my current ISP.

Network--Interfaces, click the Edit button next to WAN, click Advanced Settings tab, look near the bottom.

Excellent, thanks I see it now.
However, even with entering an address, getting config saved, and restarting the WAN component, the WAN status box after restart is not displaying the over-ride MAC address but I think whatever it would normally use.

Anywhere in the UI to see that the WAN is actually using the over-ride MAC, as opposed to just seeing that it is configured with an over-ride MAC (leaving and returning to the WAN advanced tab where it is configured does show what I have entered) ?

Thanks.

This,
https://github.com/openwrt/luci/issues/1100,
seems to me like override MAC address, configured via luci, may not be functional prior to builds on/after march 2021... ?