No I never did. The next thing to do was to investigate firewalling problems given what I had learned in this thread. But stupidly I managed to brick them pi and now can't use it at all.
I will get some help at some point to get the machine up and running again.
More recently though I spotted something excellent, a hosted Raspberry Pi 3 at Mythic Beasts. `i can ssh into it, and I can remotely reboot it and remotely wipe it and reinstall an o/s image automatically within a minute or so. So when I make a mess if things I am always safe, which means that I can try ignorant experiments with confidence.
That machine has a choice of three different o/s versions, I tried one version of Raspian 32-bit and now I am also on a very stripped-down Ubuntu 32-bit. (Not so easy to get proper AArch64 builds yet perhaps.)
On this machine, NTP just works. Probably due to the fact that there is no firewalling at all.
The machine is all set up to use IPv6 properly. I think it doesn't come with any global public IPv4 address, and I am just using IPv6 for everything.