While at home, my old LG 4X picked up automatically three 5GHz frequencies from local hotspots using WiFi Analyzer app. The Xperia SP doesn't display any, like the 5GHz is not there at all. Tried with all the 5GHz channels turned on in the app, as well as just a few, more common of them, to no avail. Furthermore, WiFi Analyzer is missing the 5G icon on its graph screen.
I thought it was the weak signal problem on the SP so many spoke about, but I found the WiFi performs much better at the same places and circumstances than the mentioned 4X, although at 2.4GHz. I also went to a place where I previously used a 5GHz wifi, but still nothing.
The phone is on .1.254 generic UK FW.