Jimk wrote:
We have a couple of Lenovo laptops running win10 mostly used by my
sons to do school work, gaming & occasionally by
me!

Annoyingly they both regularly but intermittently drop their
connection to the house wifi, then reconnect. Then "some time"
later they do it again, sometines it's minutes sometimes it's
hours, so I'm pretty sure it's not the router lease expiring &
renewing

The house WiFi is a Plusnet hub one with both 2.4 & 5ghz WiFi
networks (different SSIDs), I wondered if they were chopping &
changing networks bit I told one m/c to forget the 5ghz network,
& it still drops the 2.4ghz connection... Grrrr...

any pointers where to start?

Device Manager : (Wifi item) : Properties : Power Management

"Allow the computer to turn off this device to save power"

You could try unticking that and see what happens.

I don't have any Wifi here, so haven't tested stuff like that.
None of the routers were Wifi routers.

Paul