Windows 8 to 8.1 upgrade. Technicolor router not found. New driver solution.

[#1]

Pretty much self explanatory but hope it helps any other user in same boat.
Upgraded from Win8 to Win8.1 this afternoon. After restarting Network showed the neighbours' routers but not my Plusnet Technicolor device.
Ethernet cable connection worked fine.
My olde worlde netbook running XP could see and connect to Plusnet Wifi with no problem.
Updated the driver for my computer's inbuilt wi-fi adaptor ( Ralink RT5390R ) via Device Manager - even though Device Manager reported the device to be working properly ( I guess it was as it could find the neighbours' connections 😉 )
Anyway, back on line via wi-fi.
(Will duplicate post to broadband / routers forum)

[#2]

Duplicate post removed

[#3]

I had a similar problem with this upgrade on a HP system. My router at the time was a Netgear DGN2000 running DGTeam firmware.
I concluded it was a wireless-N driver issue with the PC's wireless adapter.
Not sure exactly what it is as a generic Microsoft driver is loaded for it; says it's USB but it isn't as it's onboard!