WAC510 can't save config

Hi all I have been using WAC510s at home for some time now with no issues, I recently purchased some additional devices from a well known auction site, they appeared brand-new but I'm having some challenges.

They reboot/reset fine and can be connected to as a client on my existing LAN they work perfectly in so far as I can connect to the access point on the default ssid and browse the internet and my home network.

But....

I can connect to the day_zero web page and change the country/region and time zone fine, I cannot however put in an SSID and Password. When I do sop and click Apply  I get a message saying "settings successfully applied" and then a red banner above the config section saying "Settings cannot be applied"

and... The Firmware version is V1.2.5.11 and checking for upgrade gives the "No New Firmware Popup" - My exisiting 510s are on FW 9.8.06

So the questions are:

How can I force an update if I can't get beyond the day_zero screen?

Is there anything else I can try?

Thanks in advance!