Do you still not have a phone line?
Aye, s'what I was thinking.
Can you connect to anything else on the Ethernet adapter? Config looks a bit... nonstandard.
The network engineer in me thinks that 169.254 should never be used so that it's obvious when they crop up that something is wrong. But then there's at least one example of paid work that I've done which uses them for the wireless access points VLAN. Such a cowboy.
Give it a proper IP address and see if that helps.
Definitely some totally unconventional setup going on here, which is no surprise.
I can SSH to the Pi via it - at present only the three devices are connected.
Hey, I'm still celebrating finally having a device that does 4G. :C
Yep, gonna have a go at setting up the Pi as a DHCP server, but probably tomorrow when I'm (hopefully) less tired.