Strange cabled network fault when rebooting from Windows (any version) into Ubuntu 24

In case it's helpful to anyone else ...

I have some Dell Precision M6800s & M6700s dual-booting via Grub between 
various versions of Windows and Ubuntu 24, all cabled to the LAN.  If I 
choose to move between any version of Windows and Ubuntu by rebooting, 
Ubuntu 24 cannot make a reliable cabled LAN connection, it keeps trying 
to connect but never succeeds.  However, if I choose to move between any 
version of Windows and Ubuntu by shutting down the PC in between, Ubuntu 
24 'just works', no networking problem at all.  Reboot from U24 and go 
back into U24, the situation is unchanged  -  if it was working before 
the reboot, it's working now, if it wasn't working before the reboot, it 
isn't working now.  Reboot from U24 and go back into Windows, no network 
problems in Windows at all.  Reboot from Windows and go back into any 
version of Windows, no network problems at all.

In summary, when rebooting ...
     Ubuntu 24 -> Ubuntu 24    No change
     Ubuntu 24 -> Windows      No problem
     Windows -> Ubuntu 24      U24 cannot make cabled LAN connection
     Windows -> Windows        No problem

It seems to me from this that the cabled network hardware is not being 
properly initialised when booting Ubuntu 24.  The cure is simply to 
actually power down the PC before launching Ubuntu 24

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