I will assume your running windows on your PC. How many ethernet connections does ypur "network and sharing centre" say you have? Control Panel>network and internet>network and sharing centre. You may have an inactive one listed and this needs to be activated.
Well I'm completely flumoxed. As I could access my NAS and router via my iPhone sone suggested I tether my phone to my computer whihc would force the PC to see the NAS and router.
So I tethered using a USB cable and sure enough I could access both from my PC. Not to get too complacent I then untethered my phone and re-booted my laptop and this time clicked on the Qfinder pro login and voila! up came the login page and I was abel to acces it. I then put in the IP address for the BT router and again it connected immediately.
I haven't a Scooby what changed in my laptop to now be able to access the router and NAS after tethering, but as they say don't look a gift horse in the mouth just accept it and be happy...which I am. So, issue resolved and thanks. Maybe it's a fix worth passing on.