So I bought a newer version. It crashed, wouldn't reset properly, and was a pain in the proverbial for two years. Then I got offered another for a price I couldn't refuse, and it's been much better, apart from resetting when you try to send big files too fast, and randomly overnight.
During the day today, it's died altogether, so I'm back on the unreliable one until I get something else, which will NOT be Netgear.