Well, that's the 1312-B10A's firmware updated from V.12 to the current V.14, all very painless without any requirement to restore any of my parameters (Wi-Fi MAC filters, static I/P address listings etc.) also glad to note that my "supervisor" login password did not change.
Absolutely no change in line connection speeds, SNRM, interleaving, INP etc., probably to be expected in my case as I'am currently imposing modem synch limits as a noise limiting experiment.
However, I did experience a very strange bi-product with my WD "My Cloud" NAS drive which is connected to a router LAN port, this refused to connect after the router re-boot, my normal desktop link to the NAS actually brought up the router GUI login page !!
The static I/P address on the NAS had for some reason changed ?
After quite a bit of messing about and finally performing a NAS reset, managed to get everything back to the original configuration with original, static I/P address, no data loss experienced on the NAS.
Previous router re-boots have never caused any NAS access issues so can only attribute this incident to the F/W upgrade process strange as it may seem.
Next time, will shut down the NAS before performing any router F/W updates.