More info. Since my last post I managed to connect to an R720 wirelessly using the serial number of the AP. All I could do was to edit the properties of the AP to give it a fixed IP address (I think). There is no internet signal being transmitted by the AP and also the ZD1200 still cannot find it. If I type 192.168.1.210 into my browser it won't find the AP. I have not adjusted the settings on my ZD1200 (I have only run the set up wizard and configured it for IP4 only). Also, I have also just done the quick set up on my ICX 7150 12C switch and set no other settings.
My network diagram follows.