Archer C7 behaviour when no internet
I use the Archer as a router and the internet comes into it from a plusnet Hub One ADSL modem. When I want to connect to the Hub One therefore, say, to reboot it, it goes through the Archer C7. This works fine if the internet is connected but if there happens to be an interruption in the internet connection the Archer C7 won't connect to the Hub One and just displays a tp-link status page saying there is no internet. The Hub One is still on and working, the problem being external, at the ISP.
Is there something I can change in the settings for the Archer C7 so that it will always connect to the Hub One, even if the internet is down? I have looked around in the menus but not found anything yet.
Grateful for advice.