Had to resolve Internet Connection speed issues at Feanor Outposts in Edinburgh at the weekend.
Junior had been complaining about very poor speeds, but the VDSL should be good for 75 down 20 up, which it was when it was installed.
And upon inspection, he was getting <1 down on the MS Surface tablet thing.
Wired connection to another device gave a solid 75 down, so a WiFi issue.
It's a dual-band 2.4 / 5 router, and it was using the 5GHz band.
But so was my tablet with no issues.
Downloaded a WiFi analyser, and its showing almost homeopathic signal levels on 5Ghz, but strong on 2.4.
Shut down the 5GHz on the router, forcing a re-connect to the same SSID at 2.4 and sanity is restored.
I think the issue is with the 5GHz radio on the tablet, and I should probably force it to 2.4 if that option exists.
But in the meantime, 5GHz is shut down on the router, and complaints have ceased.