You should be able to assign a permanent IP address to the V6 box in the settings for your Superhub, rather than from the V6 box, go to 192.168.0.1 in a web browser and there's a setting in there somewhere!
further to Tavis75's answer. It is always better to use the router to assign a fixed ip address then to setup one statically in the device you are connecting as that can lead to clashes amongst other things, if not done properly.
If you set up an address in your router it is NOT a fixed IP address, it's a reserved DHCP address. You will still get DHCP traffic on your network every time a "renew" is issued and you should get the reserved address every time, although it is not guaranteed. If you know enough about setting a fixed address in a device your should be able set it up so there will never be any duplicate addresses. That said, at the moment I have not yet been able to set up a fixed address in my V6, it's just greyed out. On my return to the UK I will be investigating further.
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