TommyG

Thanks for letting us know regarding the browser message you received, I'll pass that onto the team to look into further. 
Ah understood so do you think if we added http:// in front of dumaos on the card that would have been enough to indicate you need to go to it as a website rather than searching for it online? 
So with the R3 the interface will show you when there is an update available and allow you to install it right from the interface so very easy in that regard. We're slowly rolling out this firmware to increasingly more users over the coming days. You could wait for this to reach your router or I can provide it to you as a file to install manually. The firmware is mainly fixing bugs around the setup that you didn't encounter so it's not a necessity to upgrade to but I can send it to your or you could wait for the router to provide it, whichever you prefer.
I would definitely recommend going through the video above, that should really help and of course we're available if you have any questions or issues you may need help with.

Here is a setup video from one of our customers that you may also find helpful: 
We will also be making our own setup video soon. If you need any further help do let us know and we can walk you through it if needed.

Firstly, sorry to hear you had a tough time with setting up the router, we tried to make it as user friendly and as easy to setup as possible so having feedback like this from a first time buyer is invaluable and I will be definitely passing it onto the team to see what lessons we can learn to make it easier. To answer your questions:
This is just referring to what you would be connecting the R3 to, so all ethernet devices should be connected to the R3 and the only ethernet cable coming from your Sky Hub should be connected to the R3 WAN. The fiber box on the wall you can leave alone, that will be already connected to your Sky hub. It's possible you could replace the Sky hub but for ease probably better to leave it in the setup.
What was the message you received when going on the browser exactly? It should have actually redirected you to the interface automatically. The card in the box includes a QR code that says 'Get The App' scanning this on your phone should have taken you to your mobile app store to download and then launching that would allow you to use the router interface and setup. The other side of the card included a QR code that says 'Scan To Connect' that prompts you to connect to the Netduma R3 WiFi network. You can use http://dumaos or http://192.168.77.1 in your web browser to access.
I think what happened there is it probably searched Google for dumaos rather than dumaos being used as the URL, does that sound like what happened?
Did it prompt you to re-enter the credentials you just entered or did the WiFi disconnect for example and you needed to re-connect to continue? You probably did complete the wizard successfully but you can factory reset the router from the interface once you've accessed it via the DumaOS app on your phone or in a web browser using http://dumaos or http://192.168.77.1 and going to Settings (bottom left) > Troubleshooting > Factory Reset and once you've done that and waited a few minutes you can go through the Setup Wizard again.

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Based on my explanations above is there anything I didn't explain well enough that you're still unclear on? If not and that all makes sense, do you have any recommendations on what we could have done better to make it easier to setup etc?

Ok. Thanks for the info. Will let you know how it goes once I receive the R3. Many thanks 

Yes you should connect the R3 to the Sky Hub and then go through the Setup Wizard on the R3. Then on the R3 go to Settings > WAN and copy the WAN IP, then go on the Sky Hub interface and paste that into the DMZ option. Would also be best to disable the WiFi on the Sky Hub so all devices connect to the R3.