You'll understand if I blank out some of the IPs
So it's obviously bridged the relevant devices (giving br0). At this point I'm getting scared to bugger around with it
brctl delif br0 <wlan-interface>
echo "1" > /proc/sys/net/ipv4/ip_forward
ifconfigiptables -L -n
No reason to get scared. At this level (without saving anything) if anything goes wrong, just unplug your router from power and replug it, it will boot in a state as it was before.
I really wish there was a way to fix the Arduino side of this.
Not true with all routers. If I modify a setting, there is no need to save. Unless I am in safe mode, the change is immediate and permanent. Good thing I have a serial port to access the router to get the default config back.
Yeah I've changed other things on this router and changes like this are usually persistent. For example I've changed the brightness of the LEDs by simply piping numbers into the right /dev and it stays that brightness after a reboot.
for example br0 is mentioned in various scripts on the device - so what happens when the web interface tries to configure stuff using these scripts that reference br0? If the bridge is split, that means there'll be two separate devices to configure but again the web interface only expects one.
This is probably the case if you use the Web interface for configuring things. But if you use the command line I haven't seen a device yet that automatically saves that in a non-volatile storage.
But the OP doesn't seem to be interested, so we're just loosing time here.