I was using the device literally minutes before I rebooted. I can’t help but think that the answer must be staring me in the face but I’m clueless at the moment.
I can also connect to my NAS via Finder and Safari - so it isn’t a problem with the router or NAS - it must be something about Brave.
I went through all of the suggestions that applied to Mac (some were Windows or Android only). So, I have:
Rebooted the router
Cleared Brave cache
Deleted site cookies
Deleted all data related to 192.168.1.254
Disabled all extensions
Disable Shields
Flushed the DNS cache (Mac)
Flushed the DNS cache (Brave)
Changed the DNS server (Mac)
These last three ought to have been unnecessary given that I am using the router’s IP addresses.
Nothing worked so I finally tried connecting to a WiFi relay rather than directly to my router and that worked. I’m not sure what to do now - maybe I have to play around with the router’s network settings.
Very frustrating and not what I need after midnight (UK).
Brave was already permitted access to the local network but it would have been weird that I had been accessing it already before the reboot if it did not have access.
Anyway, the issue seems to have resolved itslef - which is annoying from a troubleshooting perspective - and after having accessed the router/NAS via the WiFi repeater, I can now access them directly via the router’s WiFi.
I don’t know what happened but for an hour or more I was refreshing the Brave page, quitting Brave and repeatedly trying many of the suggestions as well as rebooting my Mac.
So, problem inexplicably gone away rather than solved.