OK, thanks to the nice folk at IOSouth, the answer should anyone require it:
- Press the pinhole reset and hold down for 30 seconds.
- Wait 2-3 minutes for the R700 to recycle.
You will see the island-nnnnnn SSID appear, and you can then connect to the router and login with the default credentials (u=super p=sp-admin).
If both the R700 and your computer are connected to the same router, you can just find its IP address and enter that into your web browser.
If you connect to the R700 directly you must set a static IP on your computer of 192.168.0.x, subnet mask of 255.255.255.0 and gateway of 192.168.0.1
Then access 192.168.0.1 via the web browser.
Thanks for everyone who tried to help, and let's hope this answer assists someone else in the same quandary!
Cheers,
Kevin