@Hobba 

I had another issue before which I don't know if you have.  Unfortunately, the admin seems to have deleted that thread, so I can't refer to it.  I had problem with 2.4G network because I changed the names of the extenders using Tether; the router (AX3000) dropped the 2.4Ghz, and the 2.4G end devices then only connected to the extenders but have really bad/no network connections.

The problem was solved by resetting the extenders that I changed the name, turn off all the extenders, rebooted the router, and turn on the extenders again.

I submitted a bug report which the engineers "took" but nothing came out of it: they seemed reluctant to try my setup in their lab. 

The main problem of 1.1.0 that I am still having is that the 2.4Ghz seems to be weak.  Also (this may not be limited to 1.1.0), if the 2.4G performance seems to degrade significantly, I have to additionally reboot the router (I already set it to reboot everyday.).

With the restriction of not being able to downgrade, I am terrified at upgrading any working devices balancing with the fear of not getting security updates.  I think it is an onerous requirment/policy: you should at least be able to downgrade to your previous arrangement.

Hope it helps someone.

  @tikmok 

thanks for the response mate!

I don't have that issue but the 2.4ghz being weak/problematic since the firmware update and not being able to roll back to rule out its actually the firmware or some other issue is a big problem on tp-links part.

But hey if they aren't going to help roll this back i think i might have to look for equipment from a more helpful manufacturer...
every solution they have pointed to involves circumstances that haven't changed since the problem appeared, if the problem persists when the working firmware is reinstalled then ill start relocating wires and the router.