@Black Sheep:
Glad we are still pals and once again many thanks for your much valued input and advice.
@Alex Atkin UK & tubaman:
Thanks to both for further input regarding Wi-Fi connection speeds.
Have been reading up on the latest BT Smart Hub 2 available configuration options with respect to the Wi-Fi mesh system and will certainly investigate further.
Have read that the latest SH-2 Wi-Fi 2.4/5 G.Hz SSID's can not be separately identified which is considered a retrograde step by most.
There certainly appears to be a number of Wi-Fi configuration options that could be tried in an effort to improve throughput speed.
Unfortunately my sister's residence is located some 75 miles away so not so convenient to visit and have a play.
Tried some comparative Wi-Fi connected speed tests (Speedtest.net) with my laptop on my humble FTTC 40/10, ZyXEL VMG3925-B10B router system, using 2.4 G.Hz service, absolutely no difference in DS/US speeds from wired ethernet connection at any location in the house.
So what I would like to establish is why a FTTP 300/50 service with a BT Smart Bub 2 & 2 Disc's produce at least a 50% Wi-Fi DS speed reduction even when tested beside the Hub by comparison to a wired connection?