So after some tinkering this evening with wireshark, I have discovered that the router (Sky branded Sagemcom) only responds via one of the four ethernet ports (but you can see every other device on the network), the Ruckus Wireless access point seems to only serve the wireless and nothing else (I thought it may handle the authentication but no).
The router seems to connect a VPN within it to The Cloud network which handles the DNS servers and authentication remotley.
There was a spare ethernet port on the access point, plugged a cable from there to my laptop and it connected OK and brought up the login portal.
My next step is to attempt to bypass this, but having seen Darren's example of bypassing captive portals, I don't think I can without a remote server...