Sorry guys, we are quite evidently in different time zones, I just had to shut my eyes at 4am!
I am grateful for the advice that you both have posted and here is an update:
Unsurprisingly, I had a late start this morning!
Immediately checked the iPad ...still on "xxxC-5G" and still wouldn't accept the 2.4GHz band.
Seeing as the morning was almost gone, I decided to have a leisurely bath and trim my facial hair!
(Anyone know what God has in store for us which would require several feet of nasal hair?)
Once dressed and down stairs, I checked my Sony TV which is wirelessly connected to my router ...no internet connection, as expected.
went into settings and viewed wireless settings, and lo and behold, it was connected to "xxxC", the elusive 2.4GHz band!
Selecting "Refresh Internet Content", it did Infact draw down current content, so it is genuinely connected to the correct 2.4GHz Band!
Next, tried the TalkTalk "YouView Box" which is also Internet connected, but via "home plug" WiFi extenders.
True to form, it wasn't connected, ...this is an ongoing gripe I have with TalkTalk concerning this box which they foisted upon me!
The ****** thing needs to be rebooted every sodding day if you want to maintain an Internet connection, however, after the customery reboot, it was connected to the 2.4GHz Band!
Last of all, my PC, which should be blissfully unaware of the router's misdeeds that occurred after it had been switched off.
On booting it, it announced that it was "disconnected" which is something I have come to accept as one of Bill Gates's "Features" of Vista!
Upon viewing the available networks, the only one (of mine) that is showing is the 2.4GHz, to which it (reluctantly, as usual) connected.
Seems that the problem must lie with my router, I've only had it for a year!
My old Thomson Speedtouch never gave me a single problem during its entire 10 year lifespan!
Maybe I'm just getting old, but it seems "Fing aint wot they used to be"!
Thanks for your help, I suspect we've found the culprit and I need to get TalkTalk to send me a new router!