In reply to a post by BatBoy:

The DNS suggestion was only to allow you to access the GUI. It doesn't have a DNS server.

Am I right in thinking you don't have VDSL yet?

Understand that, I think.
I have VDSL with TT at the moment but changing to BT at end of month so I can put it online and try a hard reset. Hopefully I'll give it a go tomorrow and let you know how it goes.

Good luck

All OK now.
I put it online, let it sync and made sure I had internet access. Then pressed the reset for 10 seconds (this was not as straightforward as it could be as the button was iffy). It dropped the adsl sync and rebboted and I now have access to the web gui.
Seems odd but as hard reset required internet access.

Thanks all for your input. I'll tread carefully when I start configuring it for my network again

Great news, glad it's up and running