I've managed to work out how to get it to turn off NAT. Part way through the setup routine there is a cryptic question, which when you chose one of the other options it allows you to set no-NAT and DHCP.

However that still leaves me with a very limited web interface. It can't even do things like reserve IP addresses for given MAC addresses.

I found the firmware upgrade tool in the end, but my effort to use it have failed so far. I figured out early on that it probably needs a static IP setup on the network interface before you start, but it appears to forget what my username/password is half way through. No matter how many times I enter the correct password (or the serial number just in case) it tells me they are incorrect.

I'm beginning to wish I had stuck with my perfectly good Netgear router and just got a new access point instead

Rant over, back to trying to work out why the upgrade tool doesn't work.