Well, that "so-called fix" lasted all of 1/2 a day 😠 so decided to try a Restore, again will inform on how things go this time but from what others have fed back will not hold my breath.
Just to keep adding to others observations, I noticed the weather widget still "blinked" as though it was updating and the various hours/temp did change except the main headline temp and the "now" hour, those two remained "stuck". Also, spoke too soon regarding the iPad which also started showing this issue (partially anyhow), but after an hour or so it does resolve itself and show correct temps (ie. mirrors those on my iMac that is) so not quite as bad - what drew my attention to iPad weather not fully work was the lack of temp displayed top right in the News app sometimes, again this did resolve itself after a while.
The iPad behaviour started me thinking this is reminiscent of Apple server problems, but if others have not experienced the weather app freezing that would rule that idea out unless it's location based, so at the moment can only assume it's a bug - has anyone reported issue through https://developer.apple.com/bug-reporting/ yet?